[7] THE EEL QUESTION. 469 



to the fore part of the liver, passes along the whole abdominal cavity, and 

 ends a little distance back of the anal opening, with which, however, it 

 is in nowise connected. In these bands, which contain a great deal of 

 fat, numberless eggs are imbedded. By tearing a little piece of this 

 band with a pin and carefully wiping off the small drops of fat, one can 

 recognize the eggs with the naked eye as very small white dots. The 

 microscope, however, will distinctly reveal their form and inner con- 

 struction. They are generally round, surrounded by a skin, which forms 

 a clear transparent ring — the zona pellucida. Inside of this skin there 

 is a large mass of small grains, the yolk of the egg. In the larger eggs 

 nothing but these grains is seen, especially when the eggs have lain in 

 water for some time, because then the small grains composing the yolk 

 have congealed and become opaque. But if one takes from the same 

 ovarium the smaller and less developed eggs, one may very distinctly 

 recognize the small and entirely colorless bladder, called thePurkinjean 

 vesicle. There can, therefore, be no doubt that we have before us the 

 ovaria and eggs of the eel. The fact that it took several centuries of 

 eager search to discover these ovaria is, to some extent at least, explained 

 by the circumstance, that up to the present day all attempts to discover 

 larger and more developed eel-eggs have proved futile. It is well known 

 that there were no good microscopes till about thirty years ago. Even 

 the eel which was examined by Bathke, the only pregnant eel which 

 has been found, although its distended ovaria filled the whole abdom- 

 inal cavity, contained only very small eggs, the largest measuring .1 

 millimeter in diameter. Larger eel-eggs, on the point of cutting loose 

 from the ovaria and turning to young eels, have still to be discovered. 



Running alongside of each of the two ovaria, extending through the 

 abdominal cavity of the eel, there is nearly always an irregular band of 

 fat, with many points, developed more on one side than on the other ; 

 this is a fold of the inner skin of the abdomen. 



II. 



HISTORY OF THE EEL QUESTION (CONTINUED). — DISCOVERY OF THE 

 MALE EEL. — DESCRIPTION OF THE MALE ORGANS. — OUTWARD DIS- 

 TINCTIONS BETWEEN MALE AND FEMALE EELS. — THE EEL QUES- 

 TION IN GERMANY IN 1877. 



No less interesting than the history of the discovery of the ovaria of 

 the eel, is the history of the researches for the male organs of the eel, 

 although it is not many years old. 



In the above-mentioned dissertation by IIohnbaum-Hornschuch (1842) 

 we find the opinion expressed, that certain cells discovered by the author 

 inside the ovaria, which are said to differ from the egg cells both in 

 shape and contents, must be considered as the seminal cells of the eel, 

 which, therefore, would be a hermaphrodite. Six years later, Schliisei 



