XVII 



PROTOCHOPtDATA 



629 



upper, sterile portion of the rudiment of the ovary. In this genus 

 there is, therefore, & right and a left ovary, and a right and a left 



hyp 



oes 





FIG. 457. Illustrating the development of the genital organs in the simple Ascidian 

 iiiiijiii/lnides. (After Do Selys-Longchamps and Damas. ) 



A, young Ascidian seen I'M mi the side showing lirst trace of the genital organs. J!, the genital 

 rudiment of an ulder specimen showing incipient differentiation into ovary tcstes. C, ti-ansvei-se sect nm 

 through a genital rudiment, of a still older specimen showing the hollow ovary and the solid testes. I), 

 a considerably older genital rudiment showing the formation of ampullae liy the testes. n, aims ; at, 

 atrial cavity; e.ndxt, endostyle ; VM/I, I'udiment of genital organ; </.sl, r/x-l, the first two gill-slits; IIH/I. 

 liy]io]ihysial canal; int, intcstiim ; m, mouth; DCN, oesophagus; <>t, otolith; r, ovary; at, stomach; 



t, testes. 



testis. It must he remembered that in dona there is only one ovary 

 and one testis. 



