STKUCrUHE AND DEVELOPMENT OF VERTEBRATE OVARY. 393 



apparently replaced by a deeply stained irregular body, smaller 

 than the ordinary nuclei (PI. XVIII^ fig. 11, d. n.). This body, by 

 the use of high objectives, is seen to be composed of a number 

 of deeply stanied granules, and around it may be noticed a clear 

 space, bounded by a very delicate membrane. The granular body 

 usually lies close to one side of this membrane, and occasionally 

 sends a few fine processes to the opposite side. 



The whole body, i.e. all within the delicate membrane is, accord- 

 ing to my view, a modified nucleus; as apjiears to me very clearly to 

 be shown by the fact that it occupies the normal position of a 

 nucleus within a cell body. Semper, on the other hand, 

 regards the contained granular body as the nucleus, which he 

 compares with the spindles of Butschli, Auerbach, &c.,^ This 

 interpretation appears to me, however, to be negatived by the 

 position of these bodies. The manner in which Semper may, 

 perhaps, have been led to his views will be obvious when the 

 later changes of the primitive ova are described. The formation 

 of these nuclei would seem to be due to a segregation of the 

 constituents of the original nuclei; the solid parts becoming 

 separated from the more fluid. As a rule, the modified nuclei 

 are slightly larger than the original ones. In stage Q the following 

 two tables show the dimension of the parts of three unmodified 

 and of three modified nuclei taken at random. 



Primitive ova with unmodified nuclei — 



Nuclei. 



0-014 mm. 

 012 mm. 

 0-01 mm. 



Primitive ova with modified nuclei — 



Granular 

 Nuclei. Bodies in Nuclei. 



0-018 mm 006 mm. 



018 mm 0-00(5 mm. 



012 mm 009 mm. 



For a slightly older stage than q, the too annexed tables also 

 show the comparative size of the modified and unmodified 

 nuclei. 



Unmodified nuclei of normal primitive ova — 



014 ram. 

 0-016 mm. 

 0-014 mm. 

 0016 mm. 

 0016 mm. 



^ Loc. cit., pp. 361. 



