io6 



Scientific Proceedings (57). 



of the uterine cavity resemble in every respect closely the struc- 

 tures which I found 1 in about ten per cent, of the ovaries of young 

 guinea pigs and which I interpreted as ova developing partheno- 

 genetically in the ovaries. 



Previously some investigators as well as myself had described 

 the first irregular cleavages in the ova in atretic follicles of certain 

 young guinea pigs. My later observations made very probable 

 the development of the ova to the stage in which the anlage of the 

 nervous system and parts of the fetal placenta are formed. In 

 this case also young guinea pigs are more favorable to the develop- 

 ment of the ova. 



Our new observation confirms the correctness of our interpre- 

 tation of the structures found in the ovaries and we can, therefore, 

 state with certainty that in a considerable number of the ovaries 

 of young guinea pigs a relatively far-going parthenogenetic 

 development of the ova takes place. 



1 Arch. f. Mikrosk. Anal., Bd. 65, 1905; Journal Am. Med. Assn., May 6, 191 1 ; 

 Zeitschrift f. Krebsforchung, Bd. 11, 1912. 



