PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 339 



HERMAPHRODITE FISHES. 

 [Translation from Der Naturforscher.*] 



It is well known that the combination of two sexes in the same indi- 

 vidual is not rare among the lower animals, although far less common 

 than was supposed before the careful and accurate use of the micro- 

 scope, as, for instance, in the case of many Mollusca and Echiuoderms, 

 which were formerly thought to be hermaphrodite, and are now known 

 to be so. 



Aristotle announced that the fishes of the genus Serranus, a family of 

 percoids, were always hermaphrodite, and this fact has been established 

 by more recent investigations of Carolini in 1787 and Dufosse in 1856. 

 In a pai)er published by Dr. J. Brock, in Gegenbaur's MorpJiologisches 

 Jahrbuch it is shown that in each of the several species of Serranus 

 occurriug in the Mediterranean there are certain modifications in the 

 differentiation of the sexual organs into testicles and ovaries, as also 

 the occurrence of a special oviduct in the one and the want of it in the 

 other two species. More recently, in 1876, Syrski has shown that the 

 Gilthead {ChrysopJirys aurata) is also hermaphrodite. And here, ac- 

 cording to Brock, the respective organization of the two organs is again 

 distinct. In general, both in the Chrymphrys and the Serranus, the tes- 

 ticle lies in the walls of the ovary, but while in the latter the testicle 

 appears only as an appendage of the ovary projecting inward, in the 

 Chrysophrys it is much more highly developed, so that, on the other 

 hand, the ovary is to be considered as an attachment to be introduced 

 in the duct of the testicle. Thus in the one genus it is the ovary and 

 in the other the testicle which is most highly developed. 



In addition to this Brock states that in a very young specimen of Ser- 

 ranus no trace of testicle could be found at all. Continued and repeated 

 investigations on a large number of specimens are desirable. 



Dr. E. V. Martens, in referring to these facts, is of opinion that the 

 predominance of the male or of the female organs, hitherto considered 

 as a generic characteristic, may, after all, be only an individual feature, 

 and vary in the same genus and species according to the age or condi- 

 tion of the fish under examination, and that the first stage in the sepa- 

 ration of the sexes occurs in a manner similar to what has been observed 

 in many Mollusca. 



A periodic separation of the function, at least in the Serranus, has been 

 established by Brock, two specimens investigated by him in September 

 having numerous ripe spermatozoids in the testicle, and vas deferens; 

 but one had no eggs at all in the ovary, and the other only very young, 

 unripe ones. The fertilization of one individual by another, on account 



*OfMarch22, p. 116. 



