898 REPORT OF COMMISSIONER OF FISH AND FISHERIES. [8] 



3. That the shell appears at a point originally occupied by the blasto- 

 pore. 



4. That a first and then a second opening is formed connecting the 

 mesenteron with the exterior almost opposite the place where the blas- 

 topore is found; and that one of these openings becomes the mouth and 

 the other the anus. 



Winslow^^ (1881), while on board the American vessel Saratoga, dur- 

 ing the summer of 18S0, observed the development of an oyster from 

 the Bay of Cadiz, which he took to be the common oyster {Osirea edulis). 

 but which, as Dr. Hoek has already remarked, was probably the Portu- 

 guese oyster {Ostrea angulata). As Mr. Winslow did not discover any 

 embryos in the shell, he attempted artificial fecundation and was entirely 

 successful. After five hours the eggs had produced well developed 

 larvae, provided with a velum, a shell, and a mesenteron, all of which 

 could be plainly distinguished. The manner in which the development 

 took ])lace resembled very much that of the Ostrea virginiana. 



Bouchon-Brandely^^ (1882) has studied the mode of propagation of the 

 Portuguese oyster {Ostrea angulata) which at present is acclimatized at 

 the mouth of the Gironde. This oyster is unisexual ; its eggs develop 

 outside of the mother, and may, therefore, be cultivated in sea- water. 

 He believes if experiments made in this respect with the Ostrea edulis 

 did not succeed, this is caused by the considerable quantity of albumen 

 which the liquid of the mantle cavity contains, in which the larvie of 

 this oyster develop. According to Bouchon-Brandely, this essential 

 difference in the organization of these two species makes all attempts at 

 cross-breeding absolutely impossible, and thereby also excludes the possi- 

 bility of a bastard form which some oyster cultivators say exists. Experi- 

 ments made in this respect have proved entire failures. The fecunda- 

 tion of the Ostrea angulata, on the other hand, has proved successful. 

 The eggs and the spermatozoa, when in water, preserve their vitality 

 for several hours. Excellent results were obtained by using the sexual 

 products taken two or three hours previous from the genital organs. 

 The embryos began to move, according to the temperature, in from 7 to 

 12 hours after fecundation. The shell formed about the sixth or seventh 

 day. 



Finally, Eyder^* (1883) speaks of the mode of fixation of the larvae of 

 the American oyster. Assisted by Col. Marshall McDonald, he succeeded 

 in obtaining larvae of the eggs of the Ostrea virginiana artificially 

 fecundated. These larvae, after twenty-four hours, adliered to the sides 



i^An account of an experiment in artiticially fertilizing the ova of the Eui'opean 

 oyster (Osirea edulis). Report of Ferguson, commissioner of fisheries of Maryland, 

 1881. 



'S-De la sexualit6 chez Vhuitre ordinaire (0. edulis) at chez Vhmtre portugaise (O. augnlata). 

 Comples L'endus, &c., vol. xcv, p. 256. 



"On the mode of fixation of the fry of the oyster. Bulletin of the U. S. Fish Com- 

 mission, vol. ii, 1882, p. 383. 



