54 



STARFISH GALLERY. 



Figr. 34. 



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

 and D. Holothuria atra : from various aspects. E. Spicule from 

 sucker of Stichopm variegatus. (Magnified about 200 diam.). 



Fig. 35. 



Diagram of Water-vessels. 



cc. Circular canal, mthp.v, its Polian vesicles; from it a radial canal (u.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 niadreporite (m). 



