PEOPAQATION OF CERTAIN ECHTNODERMS. 



63 



bricated calcareous scales of the peristome, in the form, sculp- 

 ture, and proportionate length of the primary spines, and in the 

 form of the different elements of the jaw-pyramid and in that of 

 the teeth ; but the test is more depressed, the secondary spines 

 which articulate to the ambulacral plates and cover the pore-areas 

 are longer and more cylindrical, not so much flattened as they are 

 in C. papillata ; the large tulip-like pedicellarise and the long 

 thin tridactyle pedicellarise mixed with the secondary spines in 

 the northern species are wanting, or in very small number ; and 

 the minute pedicellarise of the peristome are much fewer. The 

 ovaries, which in G. papillata have the walls loaded with large 

 expanded calcareous plates, contain only a few small branched 



Fig. 4, 



Cidaris nutrix, Wy v. Thomson. 

 LINK. JOURN. — ZOOLOGY, VOL. XIII. 



