206 BULLETIN OF THE 



lateral zone of thickenings belonging to the vitellus had already 

 reached the edge of the central "area." The vitelline half-spindle 

 has been seen gradually to fade, but its complete disappearance I 

 cannot affirm from direct observation. It seems to me not entirely 

 impossible that its filaments are absorbed by the zone of thickenings, 

 and that the latter is actually converted, as in the normal method, 

 into a nuclear structure, in the vicinity of which two new stars (the 

 second archiamphiaster) make their appearance. Both of these (the 

 existence of a veritable nucleus, and the formation of tivo new stars) 

 are only assumptions. I have no direct evidence that such a nuclear 

 structure intervenes between the two archiamphiasters, nor that the two 

 asters are both formed about new centres. There are only very slight 

 indirect signs of such a condition, — indications that only warrant the 

 suggestion of a possibility. I will not on that account withhold the 

 observations. 



There is some reason for believing that the view presented in Fig. 53 

 is that of the second archiamphiaster in process of a rotation which would 

 eventually have brought its axis into coincidence with the animal radius 

 of the vitellus.* If such be the case, it seems quite j)robable that this 

 whole figure originated from a nuclear structure, in much the same man- 

 ner as the first archiamphiaster is known to arise from the germinative 

 vesicle, and that consequently this second spindle was not directly de- 

 rived from the first spindle, and that possibly both of the stars are new 

 productions. The reasons already indicated for thinking it is the sec- 

 ond, are certainly only meagre evidence to fill the place of the more 

 complete observations which are needed, but may possibly suffice to 

 make probable what I have stated as my conviction, that the figure is 

 that of the second, and not of the first, archiamphiaster. 



Perhaps the most noticeable feature of this amphiaster is the inclina- 

 tion of its axis to the supposed animal radius. This specimen is es- 

 pecially interesting, as it is the only one in which I have succeeded in 

 finding evidence of this obliquity. Such a peculiarity has often been 

 noticed by other observers in the case of the first archiamphiaster. It 

 will be'seen from Figs. 53, 54, that the spindle is not radial in position, 

 The two asters are not of equal extent, the deeper being the larger. 

 Such a difference in sharpness of limitation as I have seen in other cases 

 is not noticeable here, or at least it is much less marked than in many 

 instances. In neither star does the influence produce rays reaching to 

 the periphery ; in other words, the figure is wholly immersed in the 



* See page 189. 



