XVII 



PEOTOCHOEDATA 



629 



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

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



Fig. 457. — Illustrating the development of the genital organs in the simple Ascidian 

 Molffula ampidloides. (After De Selys-Longchamps and Damas. ) 



A," young Ascidian seen from tlie side showing first trace of the genital organs. B, the genital 

 rudiment of an older specimen showing incipient differentiation into ovary testes. C, transverse section 

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

 a considerjCbly older genital rudiment showing the formation of ampullae by the testes, a, anus ; at, 

 atrial cavity ; endst, endostyle ; gon, rudiment of genital organ ; gs^, gs^, the first two gill-slits ; liyp, 

 hypophysial canal ; int, intestine ; m, mouth ; oes, oesophagus ; ot, otolith ; ov, ovary ; st, stomach ; 

 t, testes. 



testis. It must be remembered that in Ciona there is only one ovary 

 and one testis. 



