232 BULLETIN OF THE UNITED STATES FISH COMMISSION. 



bins, Hart, Jiud others have written excellent works on the oyster, and 

 all of them reach the same conclusion.* 



We have already stated in a former report that there was a time when 

 this question of the hermaphrodism of the oyster possessed some real 

 interest ; the time when jiublic opinion went into ecstasies over the dis- 

 covery of the artificial fecundation of fish eggs by Messrs. Geliin and 

 Kemy, two fishermen of the Vosges Mountains. People lived in hopes 

 that the method of artificial fecundation which succeeded so well with 

 salmonoids might also be applied to mollusks. One began to look even 

 further — as we see from various communications made to the Academy 

 of Sciences — and hoped that our race of oysters might be improved by 

 cross-breeding. It was, therefore, important to Icnow whether the sexes 

 of this mollusk were separate. It was found that hermaphrodism was 

 the rule with the Ostrea cdulis, consequentlj" the projected plan of oper- 

 ation became impossible. 



Hermaphrodism is not the only cause which j)revents the success of ar- 

 tificial fecundation as regards the common oj'ster. Would it be possible 

 to ])ractice this method with hope of success without being previously 

 assured that the eggs are mature? and how can this be ascertained, and 

 how can the eggs be brought into direct contact with the fecundating 

 element, considering the fact that im])regnation takes place inside tin- 

 ishells, and probably in the oviducts ? And even supposing that the 

 eggs and the fecundating element could be brought together, artificial 

 fecundation would not yet yield any practical result, in view of the fact 

 that the eggs and the embryos of the Ostrea edulis, which should neces- 

 sarily be treated separately, cannot develop or even live outside of the 

 liquid secreted by the mother oyster and contained in the incubatory 

 cavity of its shell. 



The inquiry whether the oyster is a complete hermaphrodite, that is 

 to say, whether it is caj)able of generating without the aid of another 

 oyster, has given rise to very interesting researches ; but as this special 

 question of embryology can hardly be of interest in this report, we shall 

 confine ourselves to giving a brief recapitulation of the difl'erent opinions 



* By tlio generic term Ostrea cdiilis wo nuderstand most of the varieties of ojsters 

 eanglit on the coast of Enrop(\ namely, tlii^ violet-colored oyster -with white stripes, 

 called the hi-eolored oystiu' of Brittany ; the oyster with violet streaks from the basin 

 of Arcachon ; tlu^ reddish oyster from tho riv(;r Quimper; the oyster with mother-of- 

 pearl shell from the bank of Dives; the wandering oyster from the island of Ee; the 

 cinnamon-colored oyster from the river B61on and the Arcaclion b.asin ; the green oyster 

 of Marennes and La Trcmblade : the brown oyster from the roadstead of Toulon ; the 

 oyster with a thick white shell wJiich was formerly caught near Cetto, Port-de- 

 Bonc, and other places (m the Mediterranean ; the rough-shell oyster of Corsica; tho 

 Isle of Wight oyster ; the small English oyster, and two varieties, the Ostrea ihicta, 

 and the Ostrea deformis; the rose-colored oyster Irom tho cold waters of Norway ; the 

 large Baltic oyster; the thick-shell oyster from the Ionian Sea; the Adriatic oyster; 

 the Balearic oyster ; tho Santander oyster; the liorse-foot oyster; the small Toulon 

 oyster, which is also found in tho Bay of Genoa and in the B.ay of Naples, and whose 

 scientific name is Ostrea pUcatula or Ostrea stentwa. 



