PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 281 



ill France under the name of Anguille pimperneau, Dareste* found the 

 same organ. It api^ears that only in one case {Anguilla bostoniensls) 

 have living spermatozoa been found in a male eel, as we learn from a 

 communication to the Zoologischer Anzeiger, vol. ii, No. 18, p. 15, by 

 A. S. Packard. The male in this case was about 430""" long (17 inches). 

 That the finding of such specimens is so very rare should not astonish 

 us, since the young eels migrate to the deep sea, where the reproductive 

 organs complete their development very rapidly (6 to 8 weeks), when 

 spawning takes place ; the old eels, the females as well as the males, 

 dying after the reproductive act is consummated. Though on this account 

 the spermatozoa, and in most cases their testicular mother cells, are 

 wanting, the investigation of the histological structure of the organ of 

 Syrski may still bring us somewhat nearer to the truth. 



If one examines i^artially grown eels measuring 200-500™" in length 

 one will find a moderate broad band in the abdominal cavity of seme 

 of them, attached at its inner margin by a narrow duplicature of 

 the peritoneum to the air-bladder, the other margin, however, hanging 

 I'ree in the cavity of the abdomen. This band extends from the liver to 

 behind the anal opening, and is covered by thousands of fat cells. A 

 lobular organ, consisting also of fat cells, overlies the hinder portion of 

 the alimentary canal and ovarium. I found the eggs to average 0.75™™ 

 in diameter from specimens 20-50 *^™ in length. Treated with acetic acid 

 and ammoniacal carmine solution, a large nuclens and nucleolus became 

 visible. In other examples, although the fat lobules were present, the 

 broad band was absent. But in exactly the same position and along 

 the dorsal asj)ect of the abdominal cavity a quite thin band or strip of 

 tissue of glass-like transparency is attached, and likewise by a fold of 

 connective tissue (peritoneum), to the air-bladder, and extends from the 

 liver to behind the anal opening. This band or strip of tissue is cre- 

 nated along its free margin, the lobes of which measure 0.75™™ in length 

 and 0.5™™ in depth, their convex portion depending into the abdominal 

 cavity. In this Syrskian or lobed organ one finds, along the margin where 

 it is attached, a fine canal, the efferent seminal duct, which, upon being 

 tinged with carmine, becomes quite distinct, and which may also be dem- 

 onstrated by means of injections. The histological structure of the fore- 

 going lobulated organ was investigated by Freud.t He found an areolar 

 structure with connective tissue corpuscles, similar to the histological 

 structure of the immature testes of fishes. My preparations had a sim- 

 ilar appearance as long as the smaller examples were the subjects of 

 investigation. In the largest specimens of eels Avith lobulated organs 

 investigated by me (445'"'" long) 1 found cylindriform strings, which 

 passed from the bases to the tips of the lobes, and were filled with cells. 

 After repeated trials with the most different reagents, I did not succeed 

 in clearly distinguishing a nucleus in these cells. My observations 



* Compt. Reiidus, 1875. t. Ixxxi p. 159. 



t Sitzungsber. d. kiiis. Akad. d. Wisseusch., Wicii, 1877, Miirz Heft, 



