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The objects which the technical education board has had in representatives of the Central Governing Body, the technical view in its dealings with the polytechnics have been:
education board of the London County Council, and the 1. To allow to the several governing bodies the greatest possible ireedom in the conduct of social, recreative and even religious
City and Guilds of London Institute, and its duty was to consult work within the provisions of the schemes of the Charity Com as to the appropriation of funds, the organiza-London missioners.
tion of teaching, the holding of needful examina- Polytechalo 2. To secure to each polytechnic the services of an educational
tions, and the supervision of the work generally. Collado principal, who should be responsible to his governing body for the organization and conduct of the whole of the work of the
After ten years of work the London polytechnic council institution.
was dissolved in the summer of 1904 in consequence of the 3. To provide in each polytechnic a permanent staff of teachers, abolition of the technical education board of the London who should be heads of their respective departments and give County Council. when the council became responsible for all their whole time to the work of the institution, and thus to
grades of education. A statement below shows the number establish a corporate or collegiate life in the polytechnic.
4. To ensure that all branches of experimental science are taught and names of the several institutions, and the extent to which experimentally, and that the students have the opportunity of they have been severally aided by the Central Governing Body carrying out practical laboratory work, at an inclusive fee not
and the London County Council. excecding ten shillings for any one subject.
The “ People's Palace" owes its origin in part to the popu5. To provide efficient workshop instruction in all practical trade subjects.
larity of a novel by Sir Walter Besant, entitled AU Sorts and 6. To secure that the number of students under the charge of Conditions of Men, in which the writer pointed out The any one teacher in laboratory or workshop classes, or in other the sore need of the inhabitants of East London People's classes in which personal supervision is of paramount importance,
for social improvement and healthy recreation, Palace. shall not excced a stated limit (fifteen in the workshop, or twenty in the laboratory).
and set forth an imaginary picture of a “ Palace of Delight," 7. To exclude from classes students who, for want of preliminary wherein this need might be partly satisfied. Much public training, are incapable of profiting by the instruction provided;
interest was awakened, large subscriptions were given, and and to this end to restrict the attendance at workshop classes to
the Central Governing Body aided the project; but the those who are actually engaged in the trades concerned, and have thus opportunities of acquiring the necessary manual dexterity in
munificence of the drapers' company in setting aside £7000 a the performance of their daily duties.
year for its permanent maintenance released the London County 8. To furnish an adequate fixed stipend for all teachers, in place Council from any obligation to make a grant. Apart from the of a contingent interest in fees and grants.
social and recreative side of this popular institution, the edu. 9. To encourage private subscriptions and donations. 10. To establish an efficient system of inspection.
cational section, under the name of the East London Technical 11. To facilitate the advertisement of polytechnic classes, and i College, steadily increased in numbers and influence under the especially to invite the co-operation of trade societies in supporting
ostering care of the drapers' company and has now been retheir respective classes.
cognized as a "school” of the university of London under 12. To encourage the higher development of some special branch of study in cach polytechnic.
the title of “The East London College' and is being utilized 13. To utilize the polytechnic buildings as far as possible in the by the London County Council in the same way as other" schools daytime by the establishment of technical day schools, or otherwise.
14. To secure uniformity in the keeping of accounts. The regulations under which the council has
Grants to the London Polytechnics during the Session 1906-1907. attempted to secure its objects by means of grants have been changed from time to time as
Central Governing Body. London County Council. | the work of the polytechnics has developed, but they provide that the council's aid should
Mainbe partly in the form of a fixed grant to cach
tenance. institution, partly a share of the salaries of the principal and the permanent teachers, partly
Battersea Polytechnic .. 2,500
4,760 Birkbeck College
3,450 a grant on attendance, the scale depending on
Borough Road Polytechn
5,285 the subject and character of the instruction, and City of London College
3,725 parıly a subsidy (15%) on voluntary contri East London College .
nil butions. In addition to the annual grants for
4.525 Northern Polytechnic
4,145 maintenance, substantial grants for building
Regent Street Polytechnic
965 7,665 and equipment are made from time to time. South-Western Polytechnic , 1,500 2,091
6,265 Woolwich Polytechnic , The scale of grants adopted by the council for the
2,525 5,495 Sir John Cass's Institute. session 1907-1908 was the following:
2,400 i. A fixed grant assigned to each polytechnic ii. Three-fourths of the salary of the principal
Total . . . . £ 20,350 16,189 14,675 47.715 (subject to certain conditions).
ii. Fifty per cent. of the salaries of heads of approved in the above table the grants are given to the nearest pound. departments.
Up to July 1907 the total expenditure of the council upon the iv. Ten per cent. of the salaries of other teachers."
v. Fifteen per cent. on (voluntary) annual subscriptions or polytechnics, apart from the day schools, training colleges, &c., donations.
conducted in them, was about £525,000, almost exactly the vi. Attendance grants on evening classes varying from id. to same as that of the Central Governing Body, The voluntary 6d. per student-hour (subject to certain conditions of minimum grants from the central governing body include a contribution attendance, eligibility, &c.). vii. Special grants not exceeding 150 for courses of lectures on
towards a compassionate fund, and a pension fund based on particular subjects required or approved by the council.
endowment assurances for all permanent officers of the poly. viii. Special grants towards any departments which the council technics in receipt of salaries of not less than £100 a year. .. may desire to see established or maintained.
The grants received from the board of education amount ix. Equipment grants and building, grants in accordance with the special requirements of the institutions.
to about £30,000 a year, while the fees of students and members, The above grants are independent of any contributions which produce about £45,000. Voluntary subscriptions, including the council may make towards secondary day, schools or day those from city companies and other sources of income, proschools of domestic economy or training colleges of domestic economy duce about £30,000 in addition, so that out of a total expendiin the polytechnics.
ture of about £200,000 a year the council now contributes 30%, : With a view to a due division of labour, and also to the co- the Central Governing Body 18%, fees 221%, the board operation of the public bodies concerned, the “ London Poly- of education 15% and city companies and other subscribers, technic Council" was created in 1894. It was composed of! 15%
pariSpecial grants toward or maintained.
in accordance with
to about £30,000 a youts
• The Goldsmiths' Institute 'ac New Cross owed its existence one-third of the population of London were not natives. They and its annual maintenance to the generous initiative of the show also that, if all England and Wales be taken together, ancient city gild whose name it bore. It was therefore entirely the number of persons between twenty and twenty-one is less independent of pecuniary subsidy from any other public body. by 12.8% than the number between thirteen and fourteen; In the year 1900 the number of class entries to this institutc but that, taking London alone, the number of persons betwcen was 7574. In 1904 the goldsmiths” company presented the twenty and twenty-one is grcater by 14.4% than the number premises, together with an annual subsidy, to the university of between thirteen and fourteen. Hence, the proportion of the London for the purposes of a training college for teachers, so inhabitants who are of an age to benefit by polytechnics and that from that date it ceased to be one of the London poly-continuation schools is in London exceptionally large. It technics, although, pending the provision of other premises, many would not be right for Londoners to complain that there is thus of the technical evening classes have been continued under cast upon them the duty of providing suitable instruction for so the London County Council by permission of the university many immigrants, for if the great city drains the rural districts with the approval of the company. The clothworkers' com of some of their best brain and muscle, she gains much from pany has also contributed £18,000 to the Northern Polytechnic their industry and productive power. The figures, however, at Holloway.
point to the necessity for taking every means possible to In all these institutions the general aims have been practically raise the standard, both physical and intellectual, of the the same, although special features have been differentiated London boy. The immigration into London of youths and Aims and in order to meet the local needs and the wishes of young men means to a grcat cxtent the substitution of the Methods. the inhabitants. In all there are laboratories and provincially trained improver or artisan for the less fit London lecture rooms, trade classes, art studios, gymnasia, provision boy, who consequently falls into the ranks of the unskilled, for manual training and domestic economy and applied science. then of the unemployed and ultimately of the unemployable. In nearly all, at first, mechanical and manual instruction But it follows from the particulars thus given that neither were the prominent objects in view, partly owing to the the supply of suitable provision for mental improvement and conditions under which grants were made by the science rational recreation for the wage-earning classes, nor the demand and art department. But of late increased attention has been for such provision on the part of the workers themselves is paid year by year to literary and humaner studies, and to commensurate with the moral and intellectual needs of a comgeneral mental cultivation, pursued pari passu with technical munity of nearly seven millions of people (four and a half and scientific training. The aid of the London organization for millions within the administrative county). The provision in
sion, now a department of the university, evening schools, institutes, classes and polytechnics is still in has been especially serviceable in providing courses of lectures some respects far inferior to that which is to be found in most and classes in literary subjects at nearly all the polytechnics. German and Swiss towns, and nceds to be greatly increased. As subsidiary to their main work, some of them have estab- In matters relating to the higher life, demand does not always lished junior continuation schools, with a view to provide precede supply; it is simply which is needed not only to satisfy suitable instruction for scholars who have left the public ele the public demand, but to create it. As new and well-devised mentary schools and are not yet prepared to enter the technical opportunities for mental culture are placed within reach, and trade classes. Although the workshops and the classes for they will be more and more appreciated. new and healthier artisans are used chiefly in the evenings, there is an increasing appetites will be stimulated, the art of employing leisure number of day students : e.g. at the Northampton Polytechnic wisely and happily will be more systematically studied, and the Institute in Clerkenwell there is a very important day school | polytechnics will become still more important centres of of engineering conducted on the "sandwich system,” the civilizing and educating influence than they have hitherto students entering engineering works for the summer months been. and returning to the polytechnic for the winter session; at the In particular, the reconstituted university of London has Battersea Polytechnic there is a very important training col- been placed in new and most helpful relation to the best of the lege for teachers of domestic economy; at Regent Street there polytechnics. By the statutes the senate of the university is are day schools in enginecring, architecture, photo-process and empowered to include in the list of " schools of the university" carriage-building; at the South-Western Polytechnic there are all institutions which are duly equipped and able to furnish important schools of mechanical and electrical engineering and suitable instruction of an advanced and scholarly type; and a training college for women teachers of physical exercises; also to recognize all thoroughly qualified professors in their at the Northern Polytechnic, as at Battersea, there is a training several faculties and subjects as “teachers of the university," college for teachers of domestic economy, and there are although some of their classes may meet in the evening only, departments of commerce and of physics and chemistry, while and no student is to be prevented from taking a degree as an the Woolwich Polytechnic receives in the daytime, by special internal student of the university solely because he can attend arrangement with the war office, a large number of engineering classes only in the evening. There is thus a way open for the 'apprentices employed in the arsenal. In short, the schemes of due recognition of the polytechnics as part of the teaching the several institutions are so elastic that the governing bodies machinery of the university, and for the admission of the best are at liberty to open any classes or to try any educational or students as undergraduates, with all the rights of internal
which they can find a genuine local students. The great possibilities of the metropolitan univerdemand. The total number of scholars in the polytechnics sity under its new conditions were at first hardly revealed or and their branch institutions is variously estimated at from accurately forescen. But there were during the session 1906-1907 40,000 to 50,000, and the total number of regular scholars in the no less than eighty-six recognized "teachers of the university" evening schools of the council does not exceed 100,000. These on the staffs of the London polytechnics and more than 750 figures may be usefully compared with the census returns, students who were working for London University degrees which show that within the metropolitan area there are in the polytechnic classes. There is no reason to fear that 704,414 persons between the ages of thirteen and twenty- the recreative, social, manual and industrial training, to which one. It is a noteworthy fact that, whereas in the population at first the special attention of the founder of the Regent Street statistics for the whole of England and Wales the number Polytechnic was directed, will suffer from a fuller expansion at each year of age is regularly diminished by death from of the academic and literary side of “polytechnic "life. Rather eight years onwards, there is a steady increase in London, it may be hoped that the due co-ordination of the practical with year by year, from fourteen up to the age of thirty. This fact the purely intellectual purposes of these institutions will serve is owing to the constant immigration of young men and women to give to all the students, whatever their future destination
nces to the metropolis. The census commis- may be, a truer and broader conception of the value of mental sioners in their report for 1901 (p. 15) computed that more than I culture for its own sake.
See also a paper by Mr Sidney Webb, The London Polylechnic fied! walls, the external part of the introvert being closed during Institutes, in the second volume of special reports on educational retraction by a membranous collar. Zooecia either arising from subjects (1898) issued by the Education Department; the Report a stolon, without lateral connexion with one another, or laterally of the Central Governing Body of the London Parochial Charities; united to form sheets. Alcyonidium, Flustrella, Bowerbankio the Annual Reports of the London County Council; the Polytechnic (fig. 3), Farrells, Viclorella, Paludicella. Magazine, published from time to time at the institute in Regent Street; and various memoirs and papers contained in the Proceedings of the Internalional Congress on Technical Education (1897), especially two--that by Mr Quintin Hogg, detailing his own early experience in founding the first polytechnic, and that of Dr William Garnett, then secretary of the Technical Education Board.
1. G. F.; W. G.) POLYXENA, in Greek legend, daughter of Priam, king of Troy, and Hecuba. She had been betrothed to Achilles, who
(After Hincks) was slain by Paris in the temple of Apollo Thymbracus, where
FIG. 2.- Part of a Branch of Crisia eburnea. the marriage was to have been celebrated (Hyginus, Fab. 110).
8, zooecia ; *, imperfectly developed ovicell. The shade of Achilles afterwards appeared to the returning
Sub-order-5. CHEILOSTOMATA (Busk). - Zooecia with more or Greeks in the Thracian Chersonese and demanded the sacrifice
less calcified walls. Orifice closed by a lid-like operculum. Poly. of Polyxena, who was put to death by Neoptolemus, son of morphism usually occurs, certain individuals having the form of Achilles, on his father's grave (Ovid, Melam. xiii. 440 sqq.).
avicularia or vibracula. The The tragic story is the subject of the Hecuba of Euripides, the
ovicells commonly found as
globular swellings surmounting Troades of Seneca and the Polyxena of Sophocles, of which only
the orifices are not direct a few fragments remain. According to Philostratus (Heroica,
modifications of zooecia, and 20, 18), Polyxena fled to the Greeks after the murder of Achilles
each typically contains a single
egg or embryo. Membrani pora, and committed suicide on his tomb.
Flustra, Onychocella; LunaPOLYZOA, in zoology, a term (introduced by J. V. Thompson,
lites, Steganoporella, Scrupo1830) synonymous with Bryozoa (Ehrenberg, 1831) for a group
celloria, Menipea, Caberca, commonly included with the Brachiopoda in the Molluscoidea
Bicellaria, Bugula, Beania, (Milne Edwards, 1843). The correctness of this association is questionable, and the Polyzoa are here treated as a primary division or phylum of the animal kingdom. They may be defined as aquatic animals, forming colonies by budding; with ciliated retractile tentacles and a U-shaped alimentary canal. The phylum is subdivided as follows.
Class I. ENTOPROCTA (Nitsche). Lophophore circular, including both mouth and anus. Tentacles infolded, during
retraction, into a vestibule which can be
Bowerbankia pustulosa, showing pavonella, showing a pair of
the thread-like stolon from which minute avicularia on either side (fig. 1), Urnatella.
arise young and mature zooecia. of the orifice of each zooecium. Class II. ECTOPROCTA (Nitsche).
The tentacles are expanded in Lophophore circular or horseshoe some of the latter. shaped, including the mouth but not Membrani porella, Cribrilina, Cellaria, Micropora, Sclenaria, Um the anus. Tentacles retractile into an bonula (fig. 4), Lepralia, Schizoporella, Celle pora, Mucronella, introvert ("* tentacle-sheath"). Body- Smillia, Relepora, Calenicella, Microporella, Adeona.
Order 2. PHYLACTOLAEMATA (Allman). -Lophophore horse-shoe wall membranous or calcified, body
shaped, or in Fredericella circular. Mouth guarded by an epistome. cavity distinct. Specific excretory Body-cavities of zooids continuous with one another. Body-wall organs absent, with the doubtful excep- uncalcified and muscular. Reproduction sexual and by means of tion of the Phylactolaemata. Repro- "statoblasts, ".peculiar internal buds protected by a chiti ductive organs not continuous with ducts.
Fredericella, Plumatella (hg. 5), Lophopus, Cristalella, Peclinalella. Zooids usually connected laterally with Hatschek (1888) treated the Entoprocta as a division of his 1997 TO their neighbours.
group Scolecida, characterized by the possession of a primary Order 1. GYMNOLAEMATA (Allman).- | body-cavity and of protonephridia; while he placed the Ecto(Alter van Beneden.) Lophophore circular, with no epistome. procta, with the Phoronida and Brachiopoda, in a distinct group, FIG.1.-Part of the Body-cavities o zooids not continuous
the Tentaculata. Against this view may be urged the essential creeping stolon, with with one another. Body-wall not muscular. zooids, of Pedicellina Sub-order 1. TRE POSTOMATA (Ulrich);
similarity between the processes of budding in Entoprocta and belgica.
Fossil. - Zooecia, long and coherent, pris. | Ectoprocta (cf. Seeliger, Zeitschr. wiss. Zool. xlix. 168; 1., 560), a. c. Stalks of zooids matic or cylindrical, with terminal orifices,
and the resemblances in the development of the two classes. of different ages; b, their wall thin and simple in structure bud. proximally, thickened and
of the forms above indicated there is no palaeontological evidence
complicated distally. "Cavity of the zooecium subdivided
with regard to the Entoprocta. The Trepostomata are in the by transverse diaphragms, most numerous in the distal portion.
main Palaeozoic, although Heteropora, of which recent species exist, Orifices of the zooecia often separated by pores (mesopores).
is placed by Gregory in this division. The Cryptostomata are also Sub-order 2. CRYPTOSTOMATA (Vine); Fossil.--Zooecia usually
usually | Palaeozoic, and include the abundant and widely-distributed short. Orifice concealed at the bottom of a vestibular shaft, sur
genus Fenestella. The Cyclostomata are numerous in Palaeozoic rounded by a solid or vesicular calcareous deposit.
rocks, but attained a specially predominant position in the CretaSub-order 3. CYCLOSTOMATA (Busk), - Zooccia prismatic or ceous strata, where they are represented by a profusion of genera cylindrical, with terminal, typically circular orifice, not protected
and species; while they still survive in considerable numbers at by any special organ. The ovicells are modified zooecia, and the present day. The Ctenostomata are ill adapted for preserva. contain numerous embryos which in the cases so far investigated tion as fossils, though remains referred to this group have been arise by fission of a primary embryo developed from an egg. Crisia (fig. 2). Tubuli pora, Hornera, Lichenopora.
Calcareous spicules have been described by Lomas in Alcyong Sub-order 4. CTENOSTOMATA (Busk).- Zooecia with soft uncalci- Idium gelatinosum.
ind oui post of a belonion
-- Zooid of time to the mature as soon as thinus hardly on
described from Palaeozoic strata. They constitute a small proportion mented substances assume a spheroidal form, which either remains of the recent Polyzoa. The Cheilostomata are usually believed to as an inert “ brown body " in the body-cavity or is discharged to have made their appearance in the Jurassic period. They are the the exterior by the alimentary canal of the new polypide. This
dominant group at the present day, and | is formed as a two-layered " polypide-bud," which usually develops
the tentacles. In Fredericella belonging to this order it is, however, The Polyzoa are colonial animals, the circular, but the systematic position of the genus is sufficiently colony (zoarium) originating in most indicated by its possession of an "epistome," a lip-like structure
cases from a free-swimming larva, which guarding the anal side of the mouth in all Phylactolaemata and con attaches itself to some solid object and absent throughout the Gymnolaemata. - The cavities of the hollow becomes metamorphosed into the primary
tentacles open into a circular canal which surrounds the oesophagus individual, or ancestrula." In the at the base of the lophophore. This is continuous with the general
enthe is open the Phylactolaemata, however, a new colony body-cavity in the Phylactolaemata, while in the Gymnolaemata may originate not only from a larva, but it develops in the bud as a part of the body-cavity, from which also from a peculiar form of bud known it becomes completely separated. In the Entoprocta the tentacles as a statoblast, or by the fission of a are withdrawn by being infolded into the " vestibule," a depression
fully-developed colony. The ancestrula of the oral surface which can be closed by a sphincter muscle. In (Alter Allman.)
inaugurates a process of budding, con the Ectoprocta they are retractile into an introvert, the "tentacleFig. 5. -- Zooid of tinued by its progeny, and thus gives sheath" (hig. 9), the external opening of which is the "orifice" of Plumalella, with ex- rise to the mature colony. In Loxosoma the zooecium. In the Cyclostomata, further distinguished by the panded tentacles. the buds break off as soon as they become | cylindrical or prismatic form of their highly calcified zooecia, the a, Anus;
mature, and a colonial form is thus hardly orifice is typically circular, without any definite closing organ. br, Tentacles, arranged assumed. In other Entoprocta the buds in the Cheilostomata it is closed by a chitinous (rarely calcareous)
on a horseshoe retain a high degree of individuality, a " operculum" (fig. 9, C), while in the Ctenostomata it is guarded shaped lopho. thread-like stolon giving off the cylindrical by a delicate membrane similar to a piece of paper rolled into a
phore; i stalks, each of which dilates at its end | longitudinally creased cylinder. During retraction this "collar" i Ectocyst;
into the body of a zooid. In some of the lies concealed in the beginning of the introvert. It becomes visible 0, Caecum of stomach. Ctenostomata the colony is similarly when the polypidc begins to
constituted, a branched stolon giving protrude its tentacles, making off the zooids, which are not connected with one another. In its appcarance through the the majority of Ectoprocta there is no stolon, the zooids growing orifice as a delicate hyaline
Mr out of one another and being usually apposed so as to form con frill through which the ten. tinuous sheets or branches. In the encrusting type, which is tacles are pushed. found in a large proportion of the genera, the zooids are usually In the Phylactolaemata the in a single layer, with their orifices facing away from the sub outermost layer of the body. stratum; but in certain species the colony becomes multilaminar wall is a flexible, uncalcified 1.1 by the continued superposition of new zooids over the free surfaces cuticle or "ectocyst," be- lil of the older ones, whose orifices they naturally occlude. The neath which follow in suc zoarium may rise up into erect growths composed of a single layer cession the ectoderm, the of zooids, the orifices of which are all on one surface, or of two layers muscular layers and the of zooids placed back to back, with the orifices on both sides of coelomic epithelium. In a ..!4.8 is the fronds or plates. The rigid Cheilostomes which have this few Gymnolacmata the ecrits habit were formerly placed in the genus Eschara, but the bilaminar tocyst is merely chitinous, type is common to a number of genera, and there can be no doubt although in most cases the that it is not in itsell an indication of affinity. The body-wall is four vertical walls and the extensively calcificd in the Cyclostomata and in most Cheilo- basal wall of the zooecium stomata, which may form elegant network-like colonies, as in the are calcareous. The free unilaminar genus Rete pora, or may consist of wavy anastomosing (frontal) wall may remain plates, as in the bilaminar Lepralia foliacea of the British coast's, membranous and uncalcified, specimens of which may have a diameter of many inches. In as in Membrani pora (figs. other Cheilostomes the amount of calcification may be much less, 18 A, 9A), but in many the supporting skeleton being largely composed of the organic | Cheilostomes the frontal material chitin. In Flustra and other forms belonging to this | surface is protected by a caltype, the zoarium is accordingly flexible, and either bilaminar careous shield, which grows or unilaminar. In many calcareous forms, both Cheilostomes and from near the free edges of Cyclostomes, the zoarium is rendered flexible by the interposition the vertical walls and comof chitinous joints at intervals. This habit is characteristic of the monly increases in thickness genera Crisia, Cellaria, Catenicella and others, while it occurs in | as the zooccium grows older certain species of other genera. The form of the colony may thus by the activity of the "epibe a good generic character, or, on the contrary, a single genus or theca," a layer of living even species may assume a variety of different forms. While tissue outside it. The bodynearly all Polyzoa are permanently fixed to one spot, the colonies wall is greatly simplified in
its of Cristalella and Lophopus among the Phylactolaemata can crawl the Gymnolaemata, in cor slowly from place to place.
relation with the functional
ter Allman.) Anatomy. The zooids of which the colonies of Ectoprocta are importance of the skeletal
of composed consist of two parts: the body-wall and the visceral
FIG. 6. Zooid Paludicella
part of the wall. Even the mass (figs. 6, 9). These were at one time believed to represent ectoderm can rarely be recog
articulata (= ehrenbergi). two individuals of different kinds, together constituting a zooid. nized as an obvious epithe
Sca, Anus. , The visceral mass was accordingly termed the “polypide" and lium except in regions where
br Expanded tentacles in the body-wall which contains it the "zooecium." This vicw
& Ectocyst. budding is taking place, while
me, r', Parietovaginal muscles depended principally on the fact that the life of the polypide and muscular layers are always of the zooecium are not coextensive. It is one of the most re
absent and a coclomic epimarkable facts in the natural history of the Polyzoa that a single thclium can seldom be ob
O, Ovary. , 17 , PER!!!
served. The body.cavitu ia OC zooecium may be tenanted by several polypides, which successively
Desophagus.n et degencrate. The periodical histolysis may be partly due to the
.! however, traversed by mus.
D. Caecum of stomach. absence of specific excretory organs and to the accumulation of cles, and by strands of meso
il testis. Disini, X, X', Funiculi.
41 pigmented excretory substances in the wall of the alimentary dermic "funicular tissue," *,*, canal. On the degeneration of the polypide, its nutritive material usually irregular, but sometimes constituting definite funiculi (fig. is apparently absorbed for the benefit of the zooid, while the pig. '6, *, *'). This tissue is continuous from zooecium to zooecium
Crisia, Collar intervallendered for both criebter Bilaminais surfac
through perforated "rosette-plates " in the dividing walls. In species of Membrani pora the "frontal membrane," or membránous the Phylactolaemata a single definite funiculus passes from the body- free-wall, is protected by a series of calcareous spines, which start wall to the apex of the stomach. This latter organ is pigmented from its periphery and arch inwards. In Cribrilina similar spines in all Polyzoa, and is produced, in the Ectoprocta, beyond the bas
quoi osamob point where the intestine leaves it into a conspicuous caecum 1909 (fig. 6, v). The nervous system is represented by a ganglion
somsituated between the mouth and the anus. The ovary (o) and 1572 in the testis (1) of Ectoprocta are developed on the body-wall, on the naistaba o adoibai stomach, or on the funiculus. Both kinds of reproductive organs En Weg may occur in a single zooecium, and the reproductive elements pass
20 VUO when ripe into the body-cavity. Their mode of escape is unknown
5510270 in most cases. In some Gymnolaemata, polypides which develop
29 A23 an ovary possess a flask-shaped "intertentacular organ," situated - Jo 29050
bass between two of the tentacles, and affording a direct passage into the
od 290 91W mog introvert for the eggs or even the spermatozoa developed in the same
mice. zooecium. In other cases the reproductive cells perhaps pass out by
292 the atrophy of the polypide, whereby the body-cavity may become continuous with the exterior. The statoblasts of the Phylactolaemata
UITI originate on the funiculus, and are said to be derived partly from an
9 ectodermic core possessed by this organ and partly from its external mesoderm (Braem), the former giving rise to the chitinous envelope
TO and to a nucleated layer (fig. 7, ect), which later invaginates to form
33doms the inner vesicle of the polypide-bud. The mesodermic portion
p.m. becomes charged with a yolk-like material (y), and, on the germina
olos w SBSNOG tion of the statoblast, gives rise to the outer layer (mes) of the bud.
dans l vloot hit
C The production of a polypide by the statoblast thus differs in no
son bud Tomo ilus6 motto essential respect from the formation of a polypide in an ordinary | Fig. 9.-Diagrammatic Longitudinal Sections of Cheilostomatous zooecium. The statoblasts require a period of rest before germina
y ob Zooecia. tion, and Braem has shown that their property of floating at the
A, Membranipora (after Nitsche); B, Cribrilina; C. Some surface may be benefcial to them by exposing them to the action
of the Lepralioid forms. b.c., Body-cavity. cr., Cryptocyst. I.S., siya bollector
of frost, which in some
Compensation-sac. f.m., Frontal membrane.o., Orifice, through
which the tentacles are protruded. op. Operculum. p.m., Parietal
170 as bonito tolaemata in the tropics
S o would show, however, are developed in the young zooecium, but they soon unite with one without further evidence, another laterally, leaving rows of pores along the sutural lines that frost is not a factor (fig. 10). The operculum retains its op
os essential for germination. continuity with the frontal membrane
The withdrawal of the (fig. 9. B) into which the parietal muscles (After Braem.) extended polypide is are still inserted. As indications that
ho FIG. 7.-Section of a Germinating effected by the contrac
the conditions described in Membrani pora
05 Statoblast of Cristalella mucedo.
tion of the retractor
10 ann, Chitinous annulus, containing air muscles (fig. 6, mr), and may be noted the fact that the ancestrula
cavities which enable the stato- must result in an in of many genera which have well-developed blast to float.
crease in the volume of compensation-sacs in the rest of their ect. Thickened part of the ectoderm, the contents of the body. zooecia is a Membrani pora-like individual
which will give rise to the inner cavity. The alternate with a series of marginal calcareous spines, layer of the polypide-bud. increase and diminution
and the further fact that a considerable
proportion of the Cretaceous Cheilosmes, Mesoderm, forming the outer layer of volume is easily under
Scrupocellaria, Menipea and Caberea art.23.
10 goto 9
FIG. body-wall exerts a pressure on the fluid of the body-cavity and is
10.- Zooecium the cause of the protrusion of the polypide. In the Gymno frontal membrane. (iii.) In Umbonula
the frontal membrane and
the entrance laemata protrusion is effected by the contraction of the parietal
the muscles, which pass freely across the body-cavity from one part muscles of the young zooecium are like
compensation - sac on of the body-wall to another. In the branching Ctenostomes the those of Membrani pora, but they become
the proximal side of the entire body-wall is flexible, so that the contraction of a parietal covered by the growth, from the proximal opercu muscle acts equally on the two points with which it is connected, and lateral sides, of a calcareous lamina covered externally In encrusting Ctenostomes and in the Membraněpora-like Cheilo- by a soft membrane. The arrangement is perhaps derivable stomes (figs. 8 A, 9 A) the free surface or frontal wall is the only from a Cribrilina-like condition in which the outer layer of the
one in which any consider-spines has become membran
spines has become membranous while the spines themselves are
laterally united from the first. (iv.) In the Microporidae and can take place. The paric Steganoporcllidae the body-cavity becomes partially subdivided tal muscles (p.m.), which | by a calcareous lamina (cryptocyst,” Jullien which grows from pass from the vertical walls the proximal and lateral sides in a plane parallel to the frontal to the frontal wall, thus membrane and not far below it. The parietal muscles are usually act by depressing the latter reduced to a single pair, which may pass through foramina and so exerting a pressure ("opesiules") in the cryptocyst to reach their insertion. There is
on the fluid of the body. no compensation-sac in these families. (v.) Many of the Lepralioid F16.8.-Diagrammatic Transverse cavity. In Cheilostomata | forms offer special difficulties, but the calcareous layer of the frontal Sections.
with a rigid frontal wall surface is probably a cryptocyst (as in fig. 9, C), the compensation
Tullien showed that pro- sac being developed round its distal border. The "epitheca A, of Membrani pora; B, of an !
an trusion and retraction were noticed above is in this case the persistent frontal membrane. immature zooecium of Cribrilina; rendered possible by the (vi.) In Microporella the opening of the compensation-sac has p.m., Parietal muscles.
existence of a "compensa become separated from the operculum by calcareous matter, and tion-sac," in communication with the external water.
is known as the median pore." Jullien believed that this pore In its most fully-developed condition (fig. 9, C) the compensation-opens into the tentacle-sheath, but it appears probable that it really sac (c.s.) is a large cavity which lies beneath the calcified frontal communicates with the compensation-sac and not with the tentaclewall and opens to the exterior at the proximal border of the oper sheath. The mechanism of protrusion in the Cyclostomata is a culum (fig. 10). It is joined to the rigid body-wall by numerous subject which requires further examination.
boos, so muscle-fibres, the contraction of which must exert a pressure on The most singular of the external appendages found in the the fluid of the body-cavity, thereby protruding the polypide. Polyzoa are the avicularia and vibracula of the Cheilostomata, The exchange of fluid in the sac may well have a respiratory signifi The avicularium is so called from its resemblance, in its most. cance, in addition to its object of facilitating the movements of highly differentiated condition, to the head of a bird. In Bugula the tentacles.
for instance, a calcareous avicularium of this type is attached by The evolution of the arrangements for protruding the polypide a narrow neck to each zooecium. The avicularium can move as scems to have proceeded along several distinct lines: (i.) In certain a whole by means of special muscles, and its chitinous lower jaw
can amount of moonsider- spines ha cribrilina-like.co The arrangemanina covered trade