HELIX-LUCERNA. 107 



Allied to H. cara, from which it may be separated by the more 

 acute carina, which is compressed into a knife-like margin, concave 

 above and below. There is some variation in size, the form called 

 H. martiniana by Pfeiffer being scarcely larger than H. cara, and, 

 in fact, constituting a connecting link between the two species. The 

 lip is sometimes white. The spire is often flatter than the figures 

 show, and the umbilicus is as often open as closed. 



H. CARA C. B. Adams. PL 36, rigs. 37-39, 40, 41. 



Umbilicate or imperforate, depressed, acutely carinated, oblique- 

 ly striate and more or less granulated ; chestnut brown, rarely olive- 

 colored ; spire low-conoidal ; apex planulate ; sutures linear ; last 

 whorl acutely carinated, scarcely descending anteriorly ; peristome 

 expanded, white or brown, basal margin reflexed, dilated partly or 

 wholly over the umbilicus, quadri-dentate within, the inner tooth 

 generally small, often obsolete, outer tooth sometimes obsolete, 

 the two outer teeth nearer together and situated upon a narrower 

 eminence than in H. peracutissima. Alt. 13, diam. 34 mill. 



Jamaica* 



H. cara AD. Contrib. to Conch, no. 2, p. 29. (1849.) PFR., Monogr, 

 iii, p. 216 ; Conchyl. Cab. t. 126, f. 11, 12. REEVE, Conch. Icon. f. 

 223. IT. amabilis C. B. AD. Contrib. to Conch, no. 7, p. 105. 



The carina is not pinched out into so acute a keel as in H. pera- 

 cutissima. There is a var. media Ads, with light-colored carina 

 (figs. 40, 41), which approaches somewhat H. soror. The whorl does 

 not descend toward the aperture as in that species, however. 



H. SOROR Ferussac. PI. 35, figs. 27-30. 



Umbilicate, depressed, acutely carinated, solid, opaque, dark 

 brown, except for a white or yellowish band in the middle of the 

 whorl, above and below the carina; obscurely striated and 

 granulated ; spire low-conoidal ; apex planulate ; sutures linear ; 

 whorls 4 to 4?, flat, the last acutely carinated, slightly descending 

 anteriorly; aperture very oblique, transverse; peristome white, 

 expanded, basal margin subreflexed, nowhere adnate to the base 

 except at the insertion, bearing inside four acute teeth, the inner 

 one small, outer two situated upon a prominence, the three outer 

 teeth marked outside the lip by three furrows or scrobiculations. 

 Parietal callus light, thin, translucent. 



Alt, 13, diam. 30 mill.; alt. 12, diam. 33 mill. 



Jamaica. 



