PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 281 
in France under the name of Anguille pimperneau, Dareste* found the 
same organ. It appears that only in one case (Anguilla bostoniensis) 
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 actis 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 partially grown eels measuring 200-500" in length 
one will find a moderate broad band in the abdominal cavity of some 
of them, attached at its inner margin by a narrow duplicature of 
the peritoneum to the air-bladder, the other margin, however, hanging 
free 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 acetie acid 
and ammoniacal carmine solution, a large nucleus 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 aspect 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 thisSyrskian orlobed 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 with lobulated organs 
investigated by me (445™" long) I 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. Rendus, 1875. t. Ixxxi p. 159. 
t Sitzungsber. d. kais. Akad. d. Wissensch., Wien, 1877, Miirz Heft, 
