1 84 



THE ASCIDIANS. 



at.s-.. 



or.s 



-tn 



an 



end 



Fig. 94. Diagram of a dissection of Ascidia, from the right side. (After 

 HERDMAN.) 



The peribranchial cavity is indicated by the black shading. 



an. Anus. at.s. Atrial siphon, e.g. Cerebral ganglion, beneath which is the 

 subneural gland and its duct. d.l. Dorsal lamina, end. Endostyle. g. Gonad. 

 g.d. Genital duct. int. Intestine, m. Muscular mantle, oes. Aperture, leading 

 from branchial sac into oesophagus, or.s. Buccal siphon, ph. Branchial sac. 

 st. Stomach, t. Test or cellulose mantle, tn. Buccal or coronary tentacles. 

 ty. Typhlosole ; internal fold of intestinal wall, to increase the digestive surface. 



