MUSEUM OF COMPARATIVE ZOOLOGY. 315 



sumption in turn is supported by only two statements : the presence 

 of the supposed nucleus in Fig. 24, and the slight development of 

 the transverse constriction which affects the first segmentation (Fig. 



24./). 



The appearance which the author has interpreted as a nucleus admits, 



as has just been suggested, quite a different explanation, which I shall 

 directly attempt, to strengthen by further evidence. As regards the 

 second argument, — the shallowness of the constriction, — a compari- 

 son of Figs. 23 and 24 does not, owing to the incompleteness of the 

 outlines, give satisfactory proof of the author's position ; but a compari- 

 son of Fig. 1 (the egg from which the section shown in Fig. 23 was made) 

 with Fig. 24 certainly leaves the impression that the constriction is, as 

 the author claims, less advanced in the latter than in the former case, 

 and that consequently the egg seen in Fig. 24 is probably younger than 

 that shown in Fig. 23. I am, however, more inclined to agree with 

 Bobretzky as to the relative advancement of the two eggs, on account of 

 evidence which he does not seem to have given special consideration. I 

 refer to the fact that in Fig. 23 the granular zone appears to be com- 

 posed of halves which are separated by an appreciable interval, while in 

 Fig. 24 the zone appears (according to my interpretation of the figure) 

 still undivided. Granting that Fig. 23 represents a more advanced egg 

 than Fig. 24, it by no means follows that the mutual approach of the 

 rows of granules is the only possible explanation of the phenomena. 

 Not only is it possible to refer the appearance to the obliquity of the 

 granular zone, but I think a careful examination and comparison of the 

 figures will show that this latter is much the more probable interpreta- 

 tion. Assuming that such a spindle-shaped body were viewed, not per- 

 pendicularly to the axis, but obliquely, a shortening of its apparent length 

 would result. That is what is found to be the case in comparing the 

 spindles in the two figures cited, that of Fig. 24 being shorter than that 

 of Fig. 23 by about one tenth the length of the spindle. If, in answer to 

 this, it were objected that the anterior segment of the egg itself is also 

 somewhat smaller in Fig. 24 than in Fig. 23, and that consequently the 

 shortness of the spindle is the result of the diminutive size of one of the 

 eggs, I would suggest in reply, — 



(1.) That there is a greater proportionate reduction in the length of 

 the spindle than in the width of the egg ; 



(2.) That the diminished width of the anterior end of the egg might 

 also be produced by the same obliquity ; for it is reasonable to suppose, 

 from what is known of the shape of other eggs at this stage of develop- 



