141 



five ramified grooves in the lower part ; the vent marginal. 

 Recent. 



1 4. S. subrotunda. Orbicular ; the back rather convex ; 

 with five subovate ambulacra, contracted in their apices ; 

 the vent beneath the margin. Leske ap. Klein, Tab. xlvii. 

 fig. 7. Fossil. 



15. S. placunaria. Elliptical, depressed, and widest 

 in the fore part; with narrow linear ambulacra, disjoined 

 at their apices ; the vent near to the margin. Recent. 

 South Sea. 



16. S. latissima. Very large, depressed, elliptical, 

 subpentagonal, and truncated posteriorly ; with oblongo- 

 oval ambulacra ; the vent near to the margin. Recent. 

 South Sea. 



17. S. ambigena. Ovato-elliptical ; the back rather con- 

 vex ; the sides rather winding ; the ambulacra ovato-oblong, 

 pulvinated ; the vent near to the margin. Leske ap. Klein, 

 Tab. xix. fig. C. D. 



An echinanthus? This appears to approach nearly to 

 the genus clypeaster. 



GENUS X. Fibularia. Subglobular, ovoid, and nearly 

 round, with no determinate margin ; the ambulacra forming 

 petaloidal, short, narrow, and circumscribed figures ; the 

 mouth beneath, central; the vent near to the mouth, or 

 midway between it and the side. PI. ii. fig. 4, 5. 



Synon. Echinocyamus. Phelsum and Leske. 



The known species of this genus are of very small size. 

 Several species of this genus have been found by Faujas 

 St. Fond in St. Peter's Mountain, near Maestricht. 



Sp. 1. Fib. nucleus cerasi. Circumference circular; 

 upper surface globose ; sides rather sulcated ; the base 

 narrow and flat in the middle ; the small areas petal-formed 

 and rather pulvinated ; the vertex excentric with four 

 pores ; the mouth circular ; the vent smaller than the mouth, 

 and oblong. 



