216 HOMOLOGIES. 



eones of the Sea-Urchin. It is composed of com- 

 paratively small perforated plates, through which 

 pass the suckers or locomotive appendages ; and 

 on either side of the furrows are other plates, 

 corresponding to the plates of the broad zones in 

 the Sea-Urchin. Where shall we now look for 

 the five eyes ? Of course, at the tip of every ray ; 

 exactly where they were when the rays were 

 drawn up to form the summit of a sphere, for 

 then the eyes, which are now at the extremities 

 of the rays, were clustered together near the point 

 of meeting of the five zones on the ab-oral side 

 of the Sea-Urchin. Where shall we look for the 

 ovarian plates ? At each angle of the five rays, 

 because, when the broad zones of which they 

 formed the summit were divided, they followed 

 the split, and now occupy the place which, 

 though seemingly so different on the surface of 

 the Star-Fish, is nevertheless, relatively to tne 

 rest of the body, the same as they occupied in 

 the Sea-Urchin. Assuming, as we premised, that 

 the central area of the ab-oral region, forming 

 the space between the plates at the summit of the 

 zones in the Sea-Urchin, is elastic, it has stretched 

 with the spreading out of the zones, following the 

 dentation between the rays, and now forms the 

 ,»nole upper surface of the body. All the inter- 

 nal organs of the animal lie between the oral and 

 the ab-oral regions, just as they did in the Sea 



