ECHIN0DER3IA. 



V'//* 



Figure to illustrate the structure of a Starfish (Asterias rubens). 



In the ray marked I. the skin has been removed from the upper surface, and 

 the ambulacral ossicles (ao) and the suckers (s) are seen in situ ; the 

 blind outgrowths (c) from the central stomach (sp) have been dissected 

 out. In II. the gonads (g) are exposed ; and in V. the pouch-like diverti- 

 culum (p) of the stomach is to be seen (where it joins the central stomach 

 its roof has been removed to show the folded arrangement of its walls). 

 The anus («) is seen to be subcentral in position. 



