32 



DEGENERATION : 



generate, but which, I think, there is every reason to 





^4^ ,.^ .,c4 



Fjq_ 13. Two adult Ascidians : to the left Phallusia — to the right Cynthia : the 



incurrent and excurrent orifices are seen as two prominences. Half the 

 natural size. 



Fig 



Fig. 14. Fig. 15. 



14. — A colony of compound Ascidians (Botryllus) growing on a piece of sea- 



weed (Fucus). Each star corresponds to eight or more conjoined As- 

 cidians. Natural size. 

 Fig. 15. — Anatomy of an Ascidian (Phallusia). At the top is the mouth, to the 

 right the orifice of the cloaca. In the cloaca lies an egg, and above it the 

 oblong nerve-ganglion. The perforated pharynx follows the mouth and leads 

 to the bent intestine which is seen to open into the cloaca. The space around 

 the curved intestine is the body-cavity ; in it are seen oval bodies, the eggs, 

 and quite at the lower end the curved heart. The root-like processes at the 

 base serve to fix the Ascidian to stones, shells, or weed. 



believe are the degenerate descendants of very much 



