EOHINODERMA. 



107 



Fig. 1. 



A. Anchor and plate of Synapta. B, C. Tables of Eolothuria impatiens ; and 

 D. HolotJiuria atra : from various aspects. E. Spicule from sucker of 

 Stichopus variegatus, magnified about 200 times. 



Fig. 2. 



Diagram of Water-vessels. 



Circular canal, with p.v, its Polian vesicles ; from it a radial canal (v.c.) is 

 given off along the lower surface of each arm ; this supplies, by side 

 branches, the suckers, s ; connected with each sucker is a contractile 

 swelling or ampulla (a). The circular canal is in connection with the 

 exterior by s.c, the stone-canal, and opens to it by the madieporite (m). 



