SPATAXGIDiE. 69 



mouth nearly equal; spines of several forms, 

 moving on rounded knobs, which are perforated. 



C. papillata. Fig. 105 ; n.s. 



Echinus (Linn.). As Cidaris ; but the spines 

 are of one form, and their knobs are not per- 

 forated. 



E. sphsora. Fig. 106 ; 4- E. lividus. 



miliaris. melo. 



Flemingii. 



E. neglectus. E. Norvegicus. 



Family II. Clypeasterim:. 



Echinocyamus (Leske) . Body oval, with rounded 

 sides ; avenues dorsal, short ; vent between the 

 mouth, and the hinder margin. 



E. pusillus. Fig. 107 ; n. s. 



EchinaracJinius (Leske). Body nearly circular, 

 very flat, with the margin nearly sharp and entire ; 

 avenues five, dorsal, short ; vent above, close to the 

 edge. 



E. placenta. Fig. 108 ; \. 



Family III. Spatangid^e. 



Spatangas (Klein). Body heart-shaped, flattish ; 

 with avenues both above and below; four of the 

 upper ones leaf-shaped ; no dorsal impression ; 

 impression under the vent transverse. 



S. purpureus. Fig. 109 ; ^. 



