148 



15. S. cor anguinum. Cordate, subconvex ; five im- 

 pressed ambulacra, with four rows of pores ; two rows of 

 pores extended beyond the ambulacra. 



Spatangus cor anguinum. Leske ap. Klein, Tab. xxiii. 

 fig. A. B. C. D. ; Tab. xlv. fig. 12 ; and Tab. xxiii. fig. e. f. 



16. S. retusus. Cordiform, raised in the hinder part of 

 the back ; convex, but depressed, narrower and grooved 

 before ; with five ambulacra, the fifth in the dorsal groove. 

 Fossil. 



Ecliino-spatagus. Breyn, Tab. v. fig. 3, 4. Spatangus 

 depressus. Leske 9 



17. S. subglobosus. Cordato-orbiculate ; convex on both 

 sides ; with five ambulacra, doubly biporous ; the mouth 

 reniform, the vent ovate. Fossil. Leske ap. Klein, 

 Tab.liv. fig. 2, 3. 



18. S. gibbus. Cordato-abbreviated ; convex; sub- 

 gibbous ; depressed in the fore part ; the hinder part raised ; 

 with five ambulacra, doubly biporous ; the vent ovate. 

 Fossil. Encyc. fig. 4, 5, 6. 



19. S. prunella. Subglobose; gibbous in the back part ; 

 five short ambulacra with four rows of pores ; the vent at the 

 highest part of the marginal area. Fossil, from Maestricht. 



20. S. radiatus. Ovate, raised, grooved before, and there 

 rather depressed ; five ambulacra', the fifth rather obsolete 

 in the groove. Fossil, from Maestricht. 



Spatangus striato-radiatus. Leske ap. Klein, Tab. xxv. 



No echinital remains appear to have been discovered in 

 either the transition or the mountain limestone. They occur, 

 but not frequently, in the lias formation ; and, from the size 

 and form of the spines, small and setose, they may be sup- 

 posed to belong to some of the species of cidaris, or of the 

 Lamarckian genus, echinus. 



No remains of these animals are found in the sandy beds 

 of the inferior oolite, which have been deposited over the 

 Jias ; but, in the fuller's earth of the inferior oolite, placed 



