SUBJECT INDEX — SYSTEMATIC SECTION 



639 



stay here varies greatly, according to sex, cli- 

 mate and quantity of food, ranging from about 

 5 to about 20 yearq or more. All the large eels 

 are females; the males seldom exceed 45 cm. 

 in length." 



The Leptocephalus of the American eel 

 {Anguilla rostrata) was first described by 

 Eigenmann & Kennedy (1902.1) as L. 

 grassi. It is distinguished from that of 

 the European eel (A. vulgaris) by the 

 smaller number of myomeres, and in the 

 adult by the smaller number of A-ertebrae. 



Schmidt found that the breeding 

 grounds of the American species lie along 

 the entire range north of the West Indies, 

 with their central portion lying west and 

 south of the central breeding grounds of 

 the European eel. Therefore the two 

 grounds overlap and the larvse of the two 

 species are intermingled in the mid- 

 Atlantic. Schmidt says (Phil. Trans. 

 Roy. Soc. 1922, p. 204) : 



" How do the masses of larvse in the 

 western Atlantic sort themselves out, so that 

 those individuals which belong to Anguilla vul- 

 garis ultimately find themselves in Europe, 

 while those of Anguilla rostrata ' land ' on the 

 shores of America and the West Indies? " 



" In the main, the question is no longer 

 difficult to answer. In the case of the American 

 eel, the pelagic larval stage is terminated in 

 about one year; consequently the larvae have 

 not time to make the journey to Europe, the 

 distance being more than they can cover in that 

 period. It is otherwise with the European eel, 

 which takes nearly three times as long over its 

 larval development, as a result of which prac- 

 tically all of them are far away from the western 

 (American) portion of the Atlantic when the 

 time comes for them, as elvers, to seek the 

 coasts." 



Young eels (elvers) , during their ascent of 

 streams, will follow up the smallest trickle 

 of water. The following papers record the 

 obstruction of water pipes in this way. 

 Bean, B. A. 1892.3; Bishop, W. L. 1908.1; 

 Nye, W. 1883.1. 



Capture of adult eels in the open sea. 

 Cligny, A. 1912. 1,.6; Vaillant, L. L. 

 1898.3,.5. 



Marking experiments, chiefly in Finland, 

 with adult eels to determine the rate of sea- 

 ward migrations. Nordqvist, O. F. 1903.3, 

 .6, 1904.1, .2,.3; Schneider, G. 1904.10, 

 1905.9, 1908.4; Trybom, F. & Schneider, 

 G. 1908.1,.2,.3. 



Sexes of the Eel 



Because of the location of their breed- 

 ing ground, the capture of sexually mature 

 eels has been infrequent. The following 

 historical resumS, with necessary inser- 

 tion of citations, is quoted from Schmidt 

 (E. J. 1906.1, p. 138). 



" The Italian Mondini (C. 1783.1) first de- 

 scribed the ovary or female genital organ of the 

 eel in 1777, and the Dane O. F. MuUer inde- 

 pendently in 1780. The correctness of the der 

 termination was confirmed in 1838 by the Ger- 

 man Rathke (M. H. 1838.1), who later in 1850 

 (1850.1) further described a female eel, in the 

 ovary of which he could detect eggs 1/10 milli- 

 meter in diameter. Between Mondini's dis- 

 covery in 1777 of the female genital organs and 

 the discovery of the male organs a period of a 

 hundred years elapsed. The reason for this may 



be found partly in the fact, that no one had 

 noticed the pecuHarity that the male eels are 

 considerably smaller than the females, and the 

 males were consequently being sought for 

 amongst the large eels without result. In 1874 

 the Austrian Syrski (S. 1874.2, 1875.1, .2, 1876.1) 

 first described the male organ of the eel, and this 

 has very often in consequence been called 

 ' Syrski's organ,' or on account of its fold-like 

 appearance the ' lobed organ.' Syrski's ob- 

 servations were later confirmed and amplified 

 by a number of observers in various countries." 



Other papers recording male or female 

 eels; relating to the state of their reproduc- 

 tive organs, or dealing with their sexual 

 dimorphism. ♦Balsamo-Crivelli, G. & 

 •Maggi, L. 1872.1, .2, 1873.1; Barfod, 

 H. 1902.4; Calderwood, W. L. 1893.2; 

 Cattie, J. T. 1880.1; Cunningham, J. T. 

 1895.9; Freud, S. 1877.1; Feddersen, A. 

 F. 1893.1, 1894.1; Giacomini, E. 1908.1; 

 Gill, T. N. 1881.3; H. 1893.1; Hermes, 

 0. 1880.2, 1881.1; Joly de Sailly, - 1907.1; 

 Kingsley, J. S. 1879.1; Lepori, C. 1883.1; 

 •Mazza, F. 1912.1, 1913.1; Mobius, K. 

 A. 1887.1; Munter, J. A. 1873.1; Pack- 

 ard, A. S. 1879.2; Packard, A. S. & Kings- 

 ley, J. S. 1879.1; Pavesi,' P. 1880.1, 

 1887.2; Putnam, F. W. 1878.1; Rauber, 

 A. 1875.1; Ritsema, C. 1875.1; Robin, 

 C. P. 1881.1; Ryder, J. A. 1885.5; 

 Sawyer, J. G. 1879.1; Schmidt, F. 



1874.1; Trybom, F. 1902.3; Schluesser, 

 G.'Add. 1848.1; Anon. 353. 



Hermaphroditism. Ercolani, G. B. 

 1871.1, 1872.1, .2; Nardo, G. D. 1871.2; 

 Anon. 7. 



Various Leptocephali 



Occurrence of Leptocephalus brevirostris, 

 larval form of the European eel, in waters 

 of the North Atlantic and about the British 

 Isles. Bowman, A. 1913.1; Herdman, 

 W. A., Scott, A. & Johnstone, J. 1899.1; 

 Hillas, A. B. 1910.1; Hjort, J. 1910.1; 

 Holt, E. W. 1908.1, 1909.2; Petersen, 

 C. G. 1905.1; Schmidt, E. J. 1909.4; 

 Lea, E. Add. 1913.1. 



Occurrence of Leptocephalus morrisii, 

 larval form of the conger eel, in British 

 waters. Cunningham, J. T. 1891.8, 1893.5, 

 1895.4, 1897.2; Edwards, T. 1878.1; 

 Fulton, T. W. 1904.1, 1905.2; Gilson, G. 

 1908.2; Deere, H. V. Add. 1833.1. 



Various papers describing new species of 

 Leptocephalus, or other taxonomic notes, 

 Leptocephali of various regions, etc. This 

 list is assumed to be incomplete. Blegvad, 

 H. 1913.1; Haast, J. F. 1875.2; KoUiker, 

 R. A. 1853.1; Pappenheim, P. 1914.1; 

 Peters, W. C. 1859.1, 1865.1; Schmidt, 

 E. J. 1910.1; Steindachner, F. 1870.3; 

 Storer, D. H. 1848.2; •Stromman, H. 

 1896.1; Bellotti, C. Add. 1883.1; Fac- 

 ciol^, L. Add. 1883.1, .2, 1885.1; Schmidt, 

 J. 1912.1. 



General Literature 



The principal literature and the im- 

 portant steps in the development of our 

 knowledge concerning the breeding habits 

 and life history of the eel have been de- 

 tailed above. The following citations 

 include the great bulk of other references 



