130 



PAJSTAMIC DEEP SEA ECHINI. 



is more like the groove of P. Jeffreysi. In Echinocrepis setigera, Fig. 185, 

 the groove is over a fourth of the test (PI. G6, fig. /), as in E. cuneata 1 

 also, and in Spatagocystis Vlialknijai" it is nearly half the length, Fig. 186. 



20 mm. 30 mm. 80 mm. 



Fig. 187. 1 Pi.exechinuh cinctcs. 2 Ubechinus Nakksianvs. 3 U. giganteus. 



The position of the actinostome in the Urechinidse is more central than 

 in the Pourtalesire, even than in such a genus as Plexechinus, Fig. 187, 1; 

 in Cystechmus Wyvillii and G. Loveni the actinostome is also more excentric 

 than in PilematecMnus Rathbuni, Fig. 188, 3. 



18 mm. 



83 mm. 



Fig. 18S. 1 Cystechintjs Wyvii/lii. 2 C. Loveni. 3 P. Rathbuni. 



Is there not in the Clypeastroids something analogous to the intrusion 

 of the lateral posterior interambulacra between the labium and sternum 



» "Challenger" Echinoidea, PL XXXV* fig. 10. - Id. PI. XXVI*, fig. 2. 



