304 MisceUmieous. 



Lastly, we can prove the disappearance of one of the two embryonic 

 niombranes, the amnios. The disks which surround the digestive 

 tube are not liore com^wsod of hoUow sacs, but of solid lamolkv ; so 

 that a sinj^k^ membrane, the skin of the Nimfrtes, rosuhs from their 

 union. In a word, we see manifested under our eyes a remarkable 

 tendency to the suppression of the exaggerati(m of the larval state 

 which constitutes the PiUdium, and to a return to the direct mode 

 of development. 



Here, then, we have, by the side of a dcvolopracnt very hkc that of 

 the PiUdium, a very great simplification and an evident condensation 

 of the embryogcny. One step further and we arrive at the extreme 

 condensation which is observed in the larvae of Desor. AVe have 

 therefore before us an intermediate stage between the Pdidiian and 

 the larva of Desor ; and this result seems to be of incontestable 

 importance. It enables us to correlate the two widely different 

 forms of the embryos of the Nemcrtians, and shows us that the 

 nnitual relations which exist between them are analogous to those 

 which Fritz Miiller has informed us exist between the Naiqdixis and 

 the Zoifa. Like the Naujdius, the PiUdimn is the primitive form ; 

 and the larva of Desor represents a condensed form derived from the 

 former by the abbreviation of the embryogeny. — Comptes HendtiSy 

 January 25, 1875, pp. 270-273. 



On the Reproductive Organs of the Eels. By il. Syrski. 



In 1872 two memoirs appeared almost simultaneously by Italian 

 authors, who announced that they had discovered that the eels are 

 hermaphrodites. The agreement in general results was certainly 

 adapted to inspire some confidence ; but, on the other hand, con- 

 siderable divergences in the descriptions of the organs showed that 

 the question was far from being completely cleared up. These 

 differences might arise from errors of observation ; or they might be 

 ascribed to differences of organization due to the species, age, or sex 

 of the fishes examined. 



According to M. Syrski all that relates to the male organs in these 

 two memoirs is completely erroneous, and the eels are not herma- 

 phrodites at aU ; MM. Balsam o-Crivelli and Maggi were the sub- 

 jects of an illusion when they thought they had ascertained the 

 presence of spermatozoids ; the organs regarded by them as the 

 testes are nothing more than fatty bodies. 



Notwithstanding the assertions of the preceding authors, and the 

 gap which exists in the researches of M. Syrski, the probabilities 

 seem to be entirely in favour of the unisexuality of the eels. 



In these fishes the males are smaller than the females. Eighty- 

 six individuals, 218-430 millims. in length, examined by M. Syrski 

 proved to be males ; and ninety others, 275-1050 millims. long, 

 were females. The previous observers having preferred examining 

 large individuals, had only females under their inspection. 



The testes appear as nearly symmetrical paired organs, in the 

 form of long ribbons, attached, like the ovaries, along the dorsal 

 wall of the abdominal cavity. That of the right side commences a 



