ON THE EMBRYOLOGY OF THE TELEOSTS. 191 



account of the changes undergone by the eggs of Merlucius may partially fill the gap. 

 The eggs in question were taken from the fish and some were fertilized while others were 

 not. We studied only the latter. Mr. Van Vleck spent his time on the development of 

 the former, and it is sincerely to be hoped that he will soon publish his results in detail as 

 many of them are very interesting and important. 



When first seen the proloplasm of the egg of Merlucius was collected at one pole (the 

 lower) and covered about a third of the surface of the deutoplasm as a thin layer. At 

 this time no nucleus was visible, though carefully looked for. Soon there appeared, at 

 about the centre of the germinative disc, the well known aster so familiar to embry- 

 ologists (fig. 3). After about five minutes changes were noticeable in the aster ; its 

 rays grew shorter, were less distinctly defined, and finally the whole disappeared and no 

 trace of the star could be seen. The length of time from the first appearance of this 

 aster until its complete disappearance was thirteen minutes. Five minutes later the aster 

 reappeared, this time at the centre of the outer surface of the germinal disc where during 

 an interval of about ten minutes it presented the same appearance and went through the 

 same changes as before, at last disappearing as before leaving no trace of its former pres- 

 ence. After twenty minutes more had elapsed it was again seen near the edge of the disc 

 and on its outer surface, where after remaining in sight for about five minutes it again 

 faded from sight. Several additional appearances and disappearances were witnessed but 

 with no differences worthy of note and no further records were kept. These asters made 

 themselves visible with comparative suddenness, while their disappearance was more 

 gradual and is best described by the term "fading out ". Close watch was kept for the 

 formation of polar globules but without success. 



The foregoing account is by Mr. Conn, but what interpretation to place upon the 

 numerous appearances and disappearances of the aster I do not know. In another egg of 

 the same lot I saw the following phenomena : 



The appearance of only one aster was noticed and this at the outer surface of the ger- 

 minal disc and close to its outer margin. It was apparently composed of granules of pro- 

 toplasm radically arranged. At the same time of its appearance slightly marked amoeboid 

 movements of the whole protoplasmic area were seen and which were the most prominent 

 in the neighborhood of the aster and which seemingly proceeded in a slow wave-like man- 

 ner toward the aster as a centre from the circumference. This appearance was noticed for 

 about five minutes, and as the time progressed the aster gradually faded from the sight as 

 has been described above by Mr. Conn. After its disappearance two very small globules 

 or granules were seen on the surface of the germinal disc in the exact spot formerly occu- 

 pied by the aster (fig. 2). There exists in my mind considerable doubt as to whether 

 these granules were the polar globules, arising chiefly from the following reasons : their 

 very minute size, and also from the fact that neither by myself nor by Mr. Conn was there 

 witnessed anything comparable to the amphiaster (Archamphiaster of Whitman) which 



of my identification. It may be that ths exclusion of the essentially similar account of the formation of the polar glob- 

 polar globule from the egg is the normal method and this ules and their extension from the egg and, more fortunate 

 would account for the fact that it has so unfrequently been than I, saw all the stages of the operation, which were simi- 

 seen in the fishes. With the evidence of the present year I lar to those described by Fol and others in the maturation 

 feel tolerably confident that the polar globule of the text of the eggs of the Invertebrata. He however does not appear 

 (fig. 5 p. g.) was in reality such. Hoffman ('81) gives an to have seen the polar globules retained within the egg. 



