enlarged and the genital cord, g^.c, is present as a solid 

 single rov; of cells, (Compare Fig. 2, Pl.XI-I, of /an 13ene(3en 

 and Julin. ) 



A furrow, which appears opposite to tne attachment 

 of the cord, novr divides the hollow sphere into two lobes, 

 the cavities of which are not completely separated, but re- 

 main in communication. In Fig. 32, c^, the division of the 

 originally simple sphere is seen, but the section is not in 

 the proper plane to show the connection between the two cavi- 

 ties . 



One of these lobes gives rise to the testis, the . 

 other to the ovary, according to Van Beneden and Julin, who 

 have described in detail how, from the primitive, simple 

 sphere and the single cord of cells, testis, ovary, vas def- 

 erens and oviduct are all differentiated. 



Ily observations would therefore seem to support the 

 view of the Belgian authors that the male and female sexual 

 organs do not arise from separate vesicles, as described by 

 Kov/alewsky (12) in the buds of Perophqra, but are formed from 

 one and tne same rudiment. 



SUr.CvIARY OF RESULTS. 



1. The ruciiment of the Perophora bud, like that 

 of all other Ascidians, consists of two vesicles, an outer 

 and an inner one. The former is derived from the ectoderm 

 of tne stolon, tne latter from the thickened evaginated wall 



■55- 



