294 LILIAN SHELDON. 



of the subject, but shall merely touch upon some observations 

 of previous observers which seem to have a bearing on the 

 course of events in Peripatus, and call attention to those 

 points in the latter which appear to me to be of special 

 interest. 



For the sake of convenience I have arranged these points 

 under separate headings. 



The only observations which have hitherto been made on the 

 ovarian ova of Peripatus are by Stuhlmann (17) on the species 

 P. Edwardsii, and the account given by him is very incom- 

 plete. 



Origin of the Ova from the Germinal Epithelium. 



As I said above, the ova arise from the germinal epithelium 

 by a process of simple growth of any of its nuclei and an aggre- 

 gation of protoplasm round them. There are no cell outlines 

 in the germinal epithelium, a condition which Stuhlmann (17) 

 also states to exist in all the ova which he examined ; and 

 there is no distinction between such nuclei as will or will not 

 give rise to ova. 



There is no formation of nutritive and follicle cells from the 

 germinal vesicle of the ovum such as is described by Will (19), 

 as taking place in Colymbetes fuscus, or by Balbiani (1) 

 in Geophilus, but the cells of the stalk and follicle are simply 

 some of the ordinary nuclei of the germinal epithelium which 

 have this function instead of that of becoming ova. 



The germinal spot is present from the beginning in the ovum, 

 being visible as soon as the latter begins to grow beyond the 

 size of the ordinary nuclei of the germinal epithelium. It is 

 always easy to distinguish it by its size from the rest of the 

 chromatin of the germinal vesicle, and I never found more 

 than one germinal spot. Will (19) and Scharff (13) in the ova 

 of Colymbetes and osseous fishes respectively, both state that 

 a special nucleolus or germinal spot is not present from the 

 beginning, and hence conclude that it possesses no special 

 morphological importance. Although it is present from the 

 beginning in Peripatus I do not wish to maintain that its 



