FIBULARIA. ECHINODERMATA. 401 



ments complete, formed of ten furrows radiating from the sum- 

 mit to the base ; mouth subcentral ; anus inferior, oblong, 

 near the mouth. 



E. semilunaris, Lam. Ovate-oblong, subdepressed, with four pores 

 towards the vertex ; mouth oblong,, transversely oblique. Inha- 

 bits sea at St Domingo. Lam. iii. 19. 



Gen. 13. FIBULARIA, Lam. 



Body subglobular, ovoid or orbicular, with the margin none or 

 rounded, and the spines very small ; five short and narrow 

 bordered compartments ; mouth inferior, central ; anus near 

 the mouth, or between the mouth and margin. 



These animals, the smallest of the Echinides, have generally a subglobular or ovoid 

 form. 



F. Tarentina, Lam. Oval-elliptic, slightly convex above, and a little 

 concave below ; compartments short, disjoined from the apex ; 

 anus near the mouth. Mediterranean sea Lam. iii. 17- 



Gen. 14. CLYPE ASTER, Lam. Echinus, Lin. 

 Body irregular, oval or elliptical, often inflated or gibbous, with 

 the margin thick and rounded, the inferior surface concave 

 in the centre ; spines very small ; five margined compart- 

 ments, resembling a flower of five petals ; mouth inferior, cen- 

 tral ; anus near or in the margin. 



There are fossil species of this genus. 



C. rosaceus, Lam. Oval-elliptic, pentagonal, the back convex ; pos- 

 terior margin obtuse ; inferior surface corneous ; compartments 

 large. Inhabits Indian and American ocean Lam. iii. 14. 



Gen. 15. SCUTELLA, Lam. 



Body flattened, elliptical or suborbicular, slightly convex above, 

 plane below, with the margin thin, almost edged, and fur- 

 nished with very small spines ; compartments bordered, short, 

 like a flower of five petals ; mouth inferior, central ; anus be- 

 tween the mouth and margin, rarely in the margin. 



These are, of all the Echinides, those which have the shell the most flattened, and 

 the smallest spines, and may be considered in some measure as forming the passage to 

 the Asterioe. 



S. dentala, Lam. Orbicular, depressed, the disc entire ; posterior 

 margin serrated. Inhabits Indian seas. Klein, pi. 49, fig. 6, 7- 



S. sexforis, Lam. Orbicular, depressed, obsoletely truncated, with 

 six oblong pores ; anus near the mouth. Inhabits Indian and 

 American ocean. Klein, pi. 50, fig. 3, 4. 



There are some fossil species of this genus. 



SECTION III. STELLERIDES. 



Skin coriaceous, not irritable, but moveable in certain points ; 

 body short, depressed, broader than long, with angles or mar- 

 VOL, n. c c 



