FISSURELLA. 



FISSURELLA. 



Shield-shaped, conically depressed, concave within ; 

 vertex perforated ; destitute of a spire, and ob- 

 long-ovate shape. 



F. NiMBOSA. Ovate-oblong, convex, yellow- 

 ish white, and adorned with purplish-brown rays, 

 and many close-arranged longitudinal striae ; mar- 

 gin crenulated ; perforation oblong, and contracted 

 in the middle; greenish within. l^...l. W. 

 38. 99. 



F. GB^CA. Ovate-oblong, cancellated ; sum- 

 mit somewhat lateral; margin arcuated, and in- 

 ternally strongly crenated, Avhitish, and sub-rayed 

 with greenish; a dark horse-shoe mark almost 

 surrounds the perforation (English specimens of 

 this species are devoid of this latter character- 

 istic) ; inside white, l^.-.f. B. W. 38. 91. 



F. NODOSA. Oval, convexly pyramidal, whit- 

 ish, transversely annulated ; longitudinal ribs 

 armed with great tubercles, which are cleft at 

 the apex, and laterally compressed; perforation 

 oblong, contracted in the middle like a key-hole, 

 and surrounded internally with a white callus. 

 li...f. W.38. 93. 



F. BARBADENSTS. Ovatc-obloug, with un- 

 equal longitudinal nodulous ribs, yellowish white, 

 either rayed or concentrically spotted with red; 

 perforation round and sub-central; margin toothed 

 b2 



