ANGUILLA (Common eel)

As early as 1873, Baudelot suggested that the concentric zones in the scales of the common eel corresponded to periods of growth. Baudelot, E. 1873.4.

Other papers relating to the structure of the scales in regard to the determination of age in the eel. Ehrenbaum, E. & Marukawa, H. 1913.1; Gemzöe, K. J. 1907.1; Schneider, G. 1909.8; Haempel, O. Add. 1914.2.

44

CLUPEIDE

Vertebræ as well as otoliths, also opercula and other flat bones are good, but none of these give so sure results as the scales." Dahl.

Otoliths used in analysis of age of herring. Jenkins, J. T. 1902.1. - Both scales and otoliths used comparatively. Broch, H. 1907.1-1908.2.

Various papers on the determination of age and growth, chiefly by the study of the scales, in the herring (Clupea harengus) with a few on the sprat (C. sprattus). Bounhiol, J. P. 1912.1; ★Dahl, K. 1907.2, 1909.3; Fulton, T. W. 1906.1; Schneider, G. 1908.2, 1909.9; Storrow, B. 1914.1, 1915.1; Sund, O. 1909.1; Thompson, D. W. 1911.2, 1914.3; Delsman, H. C. Add. 1914.1,.2; Add. 1914.1. Caspian herring (Clupeonella). Nedozhivin, A. & Tichij, M. 1913.1.

64

PLEURONECTIDÆ

Among flatfishes, the plaice (Pleuronectes platessa) has been the chief subject of study. The structure of the otoliths, at least in younger fishes, provides a reliable index of age.

As regards older fish the otoliths become too little transparent and the annual rings too close for an absolutely safe reading. In these cases the broad flat bones of the head and shoulder girdle are good subjects and give safer results." Dahl.

Otoliths first studied as indicators of age and growth. Reibisch, J. 1899.1.

Other papers on age and growth in plaice based on study of otoliths, bones, etc. Atkinson, G. T. 1908.1; Carr, A. M. (Dab) 1909.1; Cunningham, J. T. 1905.1;

Heincke, F. 1906.1; Heincke, F. & Henking, H. 1908.1; ★Immermann, F. 1908.1; Johansen, A. C. 1905.1 (i), 1909.1, 1910.1, 1912.1; McMurrich, J. P. 1914.1; Maier, H. N. 1906.1; Meek, A. 1903.1, 1905.1; Petersen, C. G. 1903.1; ★Wallace, W. 1905.1-1911.1.

VARIOUS FISHES

Papers on the determination of age and growth by recent methods have appeared as Salmo hucho. Haempel, O. Smelt Salomon, K. 1908.1. Masterman, A. T. 1913.2.

1910.1; (Osmerus).

- Mackerel (Scomber). Nilsson, D. 1914.1. - Anchovy (Engraulis). Redeke, H. C. 1914.1. - Coregonus albula. Seligo, A. - Cynoscion regalis and Orthopristis chrysopterus. Taylor, H. F. 1916.1. Carp. Walter, E. 1901.1.

For an elaborate monograph summarizing all the data on scale reading in the herring, see Molander, in Ur. Svenska Hydrographisk-Biologiska Kommissions Skrifter for 1917.

GADIDE

"The scales as a rule are far superior to any other organ taken from the osseous system."

The following papers on growth and age determination relate chiefly to the cod (Gadus morrhua) and the pollack (G. pollachius). Carr, A. M. 1909.1; Cunningham, J. T. 1905.1; Dahl, K. 1906.4; ★Damas, D. 1909.1; Hjort, J. 1908.2; Lee, R. M. (Haddock) 1912.2; Maier, H. N. 1906.1; Redeke, H. C. 1909.1; Thomson, J. S. 1902.1, 1904.1, 1904.2; Winge, O. 1915.1.

Contrary to the almost universal opinion that the scales of fishes increase in size by annual growth rings, Brown (Alfred W. 1903.1) believes that in the cod, haddock, and whiting, the scales are annually shed after spawning until the age-limit of spawning is reached when no further shedding takes place.

For additional references to scale studies Growth on salmon, see below under both Atlantic and Pacific salmons under Salmonida.

LONGEVITY

Age attained by fishes

Records of ages attained by fishes. In some cases, the records are of fishes kept in aquaria; in others known individuals have been under observation in the ponds of European monasteries or marked specimens are alleged to have been taken from the moats of feudal castles.

Such records are as follows. - Carp (375 yrs.). Baird, S. F. 1872.9; Mehwald, 1873.1. Carp (38 yrs.). Noll, F. C. 1879.2, 1882.1. - Carp (300 yrs.). Suffield, R. R. 1874.1.

Pike (267 yrs.). Baldinger, E. G. 1802.1. Loach (260 yrs.). Bötticher, W. 1902.1. -Goldfish (30 yrs.). Essing, L. 1898.1. Trout (19 yrs.). HarvieBrown, J. 1898.1. Sea bass (21 yrs.). Townsend, C. H. Add. 1913.5. Miscellaneous items on longevity in - Carp. Falke, W. 1874.1. Pop. art. Trout. in French. Oustalet, E. 1900.1. Stone, L. 1872.5. - Goldfish. Riepe, E. Add. 1906.1.

For the "intelligence of fishes comprising their comparative psychology, and for technical studies on habit formation, etc., see under Behavior.

For the living together or association of fishes with other fishes, or with invertebrates, see under Commensalism and symbiosis.

For accounts of sharks attacking men, swordfish attacking whales, etc., see under Predatory fishes.

See also under such related topics as Aestivation; Food of fishes; Hibernation; Locomotion; Migrations; Parasitic fishes; Sleep of fishes; etc. References to the life-histories, etc., of particular fishes will be found under the various families and genera to which they refer.

Chiefly miscellaneous and unclassified items on the habits of fishes. Abel, O. 1907.1; Aflalo, F. G. 1902.2, 1904.2; Baird, S. F. 1876.8; Beckford, F. J. 1897.1; Beckmann, J. 1769.1; Blake, J. H. 1870.1; Blanchard, C. E. 1866.1; Carter, R. 1884.1; Coles, R. J. 1910.1; Coste, P. 1858.1; Dollo, L. 1895.1; Ehrenbaum, E. 1909.2; Gray, J. E. 1861.1; Groos, R. 1902.1; Huet, P. 1904.1; Nusbaum, J. 1880.1; Osburn, R. C. 1913.2; Selous, E. 1911.1; Shufeldt, R. W. 1902.2; Smith, T. 1806.1; Tosh, J. R. 1903.1; Verrill, A. E. 1871.2.

Abbott, C. C. 1884.2. Labrax. Akers,

G. F. 1879.1.

1869.1. 1884.4. 1871.2.

Mullus. Couch, J. Centrarchida. Mather, F. - Micropterus. Tisdale, S. T. Ruvettus. Becke, L. Add. 1897.1, 1909.1. Capros. Cunningham, J. T. Add. 1888.1.

Scleroparei. Habits of Cottus. Bade, E. 1899.4; Gill, T. N. 1908.2. -Myoxocephalus. Gill, T. N. 1905.15.

Liparis. Smith, W. A. Add. 1885.1. Scombriformes. Habits of Scomber. Allen, E. J. 1897.3; 1909.1; Cunningham, J. T. 1902.2. -Lepidopus. Robson, C. H. 1876.1, 1884.2.

Habits of Umbra. Abbott, C. C. 1875.2. -Esox. Curtis, G. 1861.1. Anableps. Le Conte, J. L. 1861.1; Smith, J. P. G. 1850.1; Beebe, M. B. & Beebe, C. W. Add. 1910.1.

Sub-order Malacopterygii

Habits of Thymallus. Ainsworth, S. H. 1874.1; Rutland, J. 1878.1. PomaMallotus. tomus. Ayres, W. O. 1852.1. Atwood, N. E. 1871.1. Alosa. Barfurth, D. 1874.1, 1876.1; Chapman, P. 1875.1. - Herring. Chapman, P. 1875.1. - Pilchard. Cornish, T. 1883.1. -08teoglossum. Haseman, J. D. 1911.2. Coregonus. Milner, J. W. 1877.1.

Sub-order Ostariophysi

Habits of Gymnotus. Bradley, T. 1838.1; Sachs, C. 1877.1, 1881.1. Phoxinus. Bruyant, C. 1898.1. North American Silurida. Kendall, W. C. 1904.1, 1910.1. Tinca. Lunel, G. 1874.2. Sainville, E. 1908.1. ton, H. Add. 1833.1.

Ameiurus.

- Carassius. Strat

Habits of Teleostean fishes of various other sub-orders

Hemiramphus. Andrews, W. 1849.3. - Orthagoriscus. Binney, A. 1842.1. Belone. Cunningham, J. T. 1902.2. Syngnathus. Gray, J. E. 1861.1. Mer luccius. Nye, W. jr. 1887.2. Antennarius. Whitmee, S. J. 1875.1. -Gadida. Atwood, N. E. 1866.1,.2.

For further data on habits of fishes, see under Natural History under the fish in the Systematic section.

VARIOUS SPECIFIC HABITS

For specific habits treated elsewhere, see cross-references at the beginning of this section.

For the structure and relationships of the mouth, see Oral cavity under Alimentary Canal. For the musculature of the head, see Cranial and visceral muscles under Myology.

For the external open sac of the olfactory organ, see Nares under Olfactory organs.

For the bony framework of the head, see Skull.

For an outstanding treatise on the morphology and development of the head, see Locy, W. A. 1895.1.

Embryology and development General papers. Ayers, H. 1891.1; Froriep, A. 1902.2; His, W. 1894.2; Kupffer, C. W. 1893.3, 1896.1; Minot, C. S. 1897.1.

Development of the head in Cyclostomata. Petromyzon. Koltzoff, N. K. 1902.1; Kupffer, C. W. 1893.1 (ii, iii) - Bdellostoma. Kupffer, C. W. 1899.2.

Development in Selachii. ★Froriep, A. 1901.1; Hoffman, C. K. 1894.1.

Development of the head in Neoceratodus. Greil, A. 1908.1, 1913.1 Acipenser. Kupffer, C. W. 1891.2, 1893.1 (i); - Gobius. Pollard, H. B. 1894.2.

"Cirrhostomial" origin of the head. Pollard, H. B. 1894.1, 1895.1; - Phylogenetic origin. Ziegler, H. E. 1908.2.

Metamerism of head

Most of the references given below under Morphology include also Metamerism. In this connection, see also Embryo formation and Medullary tube under Embryology.

General researches on metamerism of the head. Dohrn, F. A. 1890.1; Hatschek, B. 1906.1, 1909.1, 1910.1; Hill, C. 1899.1, Add. 1900.1; Locy, W. A. 1897.1; Neal, H. V. 1898.1; Rabl, C. 1892.2; Severtzov, A. N. 1895.1; Wijhe, J. W. 1886.2; Kingsley, J. S. Add. 1896.1.

Metamerism of the head from the standpoint of the nervous system. Hawkes, O. A. 1905.2; Johnston, J. B. 1905.3; Neal, H. V. 1898.2; Stockard, C. R. 1908.1.

Metamerism of the head in Cyclostomata (Petromyzon). Kolikov, N. K. 1901.1, Add. 1899.1; Koltzoff, N. K. 1899.1; Neal, H. V. 1915.3.

Metamerism in Selachii. ★Brohmer, P. 1909.1; Dohrn, F. A. 1882.2 (xv, xviii, xxi, xxii); Killian, G. 1891.1; N. Severtzov, A. 1898.1,.2, 1899.2; Locy, W. A. Add. 1895.1; Matveev, B. Add. 1914.1.

Morphology of head

Miscellaneous and general papers on the morphology of the head of vertebrates including fishes. Ayers, H. 1890.1; Chaine, J. 1905.1; Froriep, A. 1902.1; Hilgard. T. C. 1857.1; Marshall, A. M. 1879.1; Neal, H. V. 1898.1; Norris, H. W. 1891.1; MacMurrich, J. P. Add. 1884. 1.

Morphology of the head of various fishes. Scomber. Allis, E. P. 1903.4. - Embryo of Chlamydoselachus. Brohmer, P. 1909.1. Dipnoi. Fürbringer, K. 1904.3. Pristis and Pristiophorus. Hoffmann, L. 1912.1. -Amphioxus. Wijhe. J. W. 1901.1. Acanthias, Platt, J. B. 1891.1.2. - Macrurida. Pfüller, A. 1914.1. Anterior head cavities; structure and development, chiefly in Selachii. Boeke, J. 1903.1; Marshall, A. M. 1881.1; Platt, J. B. 1890.1; Reighard, J. E. 1901.1. Chlamydoselachus and Spinar. Brohmer, P. 1909.1.

For the development of the head mesoblast, see under Mesoderm in section or Embryology.

Snout of fishes.

Pereyaslavtzeva, S.

1876.1. -Occipital region of Trutta. Willcox, M. A. 1899.1. parative anatomy. 1877.1.

Face of fishes, com Winther, G. P. 1875.2.

Structure and biological significance of the "saw of Pristis and Pristiophorus. Kölliker, R. 1860.5; Pappenheim, P.

1905.5.

For Frontal gibbosity, a swelling or protuberance on the heads of certain male fishes, see under Sexual dimorphism.

HEARING AND THE STATIC SENSE

Comprising the functions of the membranous labyrinth or ear.

For the morphology of the membranous labyrinth, see under Auditory organs.

For a complete résumé of the literature on hearing and the static sense in fishes, see ★Mangold, E. Add. 1912.1.

HEARING

Or the sense of audition

It has not yet been conclusively demonstrated that all fishes react to sound-waves.

Kreidl noted no reactions in goldfishes from vibrating rods held both in air and water, except when the fishes had been made more sensitive by strychnine and then the reactions took place even with the ear removed. It has, however, since been objected by Bigelow that the entire ear was not removed.

Parker (1904.2), experimenting with Fundulus and using the sustained slow vibrations of a bass viol string, observed reactions (fin movements) in only 18 per cent of fishes when the auditory nerves were cut, but in 94 per cent when the ears were intact and the skin insensitized. He thus definitely concluded that fishes react to sound waves.

Zenneck working with Alburnus and Leuciscus concluded that fishes do hear. He used an electric bell under water and noted activity when the bell was rung and sound-waves produced but inactivity when a piece of leather placed under the clapper of the bell inhibited the sound waves and produced mechanical vibrations instead. Bernoulli, repeating these experiments with eels and trout, obtained only negative results.

Hearing in fishes considered impossible on grounds of brain structure. Edinger, L. 1908.2.

Researches on detached heads of pike; on receiving stimulus of sounds through water, the otolith organ shows an increase of electronegativity indicating momentarily active condition of the nerve and accepted as showing possibility of hearing. ★Piper, H. Add. 1906.1, 1911.1.

Evolution of hearing in vertebrates. lem, V. Add. 1913.1.

Wil

Investigations of a technical or scientific nature on the sense of hearing in fishes. Bernoulli, A. L. 1910.1; Bigelow, H. B. 1904.1; Haempel, O. 1911.1; Körner, O. 1905.1; Kreidl, A. 1895.1, Add. 1896.1; Lafite-Dupont, J. 1907.1; Lee, F. S. 1898.1; Maier, H. N. 1909.1; Marage, 1906.1; Nollet, 1813.1; ★Parker, G. H. 1903.3, 1904.2, 1909.3; 1910.4; Zenneck, J. 1903.1, 1904.1.

Hearing in the blind cave-fish, Amblyopsis. Eigenmann, C. & Yoder, A. 1899.1; Payne, F. 1909.1.

Effects of explosive sounds. Parker, G. H. 1913.1; Zur Mühlen, M. 1911.26.

Sound as a directing influence in movements. Parker, G. H. 1910.2, 1912.2. Movements of eye determined by hearing. Kubo, I. Add. 1906.1.

Observations, including anecdotes, miscellaneous notes, records, etc., recording the

belief of their writers that fishes possess the ability to hear.

Text in English. Baker, A. F. 1876.1; ★Bateson, W. 1889.1; Bell, J. C. 1904.1; Clapham, T. 1878.1; Lockington, W. N. 1879.3; Mackintosh, H. W. 1876.1; Redding, B. B. 1879.5.

Text in German. Beer, T. 1896.1; Blochmann, F. 1903.1; Brüning, C. 1906.1; Lang, A. 1902.1; Lenz, E. 1906.1; Piper, H. 1906.1; Plehn, M. 1905.2; Reeker, H. 1898.1; Roth, W. 1910.1; Simroth, H. R. 1897.1; Sprenger, W. 1900.5; Zacharias, E. O. 1906.1; Anon. 553; Hensen, V. Add. 1904.1; Meyer, M. Add. 1909.1; Reinhart, H. Add. 1913.1.

- Dutch.

Texts in other languages. Baster, J. 1762.2. Italian. Ducceschi, V. 1903.1. -French. Geoffroy-SaintHilaire, E. 1824.3,.10. Hungarian. Gorka, S. 1906.1. Swedish. Iverus, I. E. 1899.1. Norwegian. Møllers, H. T. 1865.1. - Spanish. Rivera, E. 1905.1. Latin. Camper, P. Add. 1763.1. Early references, in Pre-Linn. section. Arderon, W. 1750.1; Brockelsby, R. 1750.1; Camper, P. 1756.1; Denso, J. D. 1756.1; Klein, J. T. 1740.1-1747.1; Maurer, F. 1713.1; Nollet, J. A. 1746.1; Seger, G. 1688.1.

STATIC SENSE

Or maintenance of equilibrium Including the perception of progressive movements and of position in space. For Hydrostatic equilibrium, see under Air bladder.

For a related subject, see Locomotion. The functions of the lateral line organs are intimately related to the general subject of hearing. For references, see under Lateral line system.

For a complete review of the literature on the static sense, see ★Mangold, E. Add. 1912.1.

Breuer's theory of semicircular canals and otoliths as organs for sensations of acceleration of movement or for sense of rotation. ★Breuer, J. 1874.1, 1890.1.

Researches on the maintenance of equilibrium, the functions of the semicircular canals, and otoliths, etc., through the destruction or excision of the membranous labyrinth on either one or both sides, transection of the auditory nerves, etc. Ayers, H. 1894.1; ★Bethe, A. 1894.1, 1899.1; Carazzi, D. 1898.1; Cyon, E. 1878.1, 1900.1; Ewald, W. F. 1907.1; Fröhlich, A. 1904.1; Gaglio, G. 1902.1; LafiteDupont, J. 1905.1; Lee, F. S. 1894.1, 1898.1; Monoyer, F. 1866.1,.2; Parker, G. H. 1910.1; Quix, F. H. 1903.1,.12;

Sewall, H. 1882.1, 1884.1; Steiner, J. 1886.3, 1888.1; Chabry, L. M. Add. 1884.1; Kreidl, A. Add. 1892.1; Kubo, I. Add. 1906.1; Loeb, J. Add. 1891.2.

For effects of extirpation of canals and otoliths in the asymmetrical flounder, unfavorable to otolith hypothesis, see Lyon, E. P. in Amer. Journ. Physiol., 1899, vol. iii, pp. 98-104.