256 EMARGINULA. 



notched by the impression of the ribs ; inside porcelain-white and 

 nacreous, exquisitely and closely but irregularly lineated in a con- 

 centric direction ; the edges of the slit and groove are thickened. 

 (Jeffr.) Length 28, breadth 20 mill., or less. 



West coast of Scotland ; Ireland ; off the Scandinavian coast. 



E. crassa J. Sowb., Min. Conch, p. 73, t. 33, upper figs. — Forbes 

 & Hanley, Hist. Brit. Moll, ii, p. 481, t. 63, f. 2 ; t. 200, f. 2.— 

 Jeffreys, Brit. Conch, iii, p. 263, t. 59, f. 4. 



The young differs from E. fissura of the same size in being more 

 depressed, and in its peculiar sculpture. In that species the ribs 

 are strong, and the surface is coarsely cancellated ; in this the ribs 

 are fine and more numerous, and the surface is delicately granu- 

 lated. The rows of small white dots are always visible in E. crassa ; 

 and the slit is shorter relatively to the size of the shell. (Jeffr.) 



Indo-Pacific species. 

 Group of E. puncticulata. 



Shell rather elevated, unicolored whitish or yellowish ; apex pos- 

 terior; surface finely ribbed and latticed. 



E. fenestrella Deshayes. PL 41, figs. 44, 45, 46. 



Shell ovate-oblong, narrow, white, rather thick, very inequilateral, 

 ornamented with numerous radiating riblets ; having fiat, regular 

 transverse stria?, the intervals excavated into circular pits. Middle 

 rib broad, excavated, ornamented with numerous appressed, arched 

 scales. Apex acute, much inclined backward. Fissure short, wide ; 

 margin crenulated. Length 10, breadth 7, alt. 4 mill. (Dh.) 



Island of Reunion. 



E. fenestrella Dh. Moll. Reunion, p. 49, t. 7, f. 12-15. 



The surface has 24 radiating ribs. 

 E. bicancellata Montrouzier. PL 64, fig. 42. 



Shell elongated oval, summit acute, salient, recurved backward 

 and situated at the posterior fourth of the shell's length. Front 

 slope very convex, back slope straight ; yellowish-white. Sculp- 

 tured with 15-17 strong ribs, rendered very perceptibly nodulose by 

 by the intersection of concentric less salient ribs ; the decussation 

 resulting in a strong latticing of the whole surface. Toward the 

 margins the number of ribs is doubled by the intercalation of smaller 



