HELIX-LUCERNA. 117 



H. INVALIDA C. B. Adams. PI. 38, figs. 81-86. 



Smaller than the several preceding forms ; outer two teeth united 

 at their bases as in H. simson ; inner tooth small, often wanting ; 

 teeth smaller, not extending nearly so close to the parietal wall as 

 in the several preceding species. 



Imperforate, rarely umbilicate, depressed-globose, solid, opaque, 

 somewhat shining, chestnut-brown, with a peripheral light fascia, 

 base somewhat paler ; surface densely finely granulate ; spire more 

 or less elevated, obtuse ; apex glossy, corneous ; sutures somewhat 

 impressed ; whorls 4i, slightly convex, slowly widening, the last 

 rounded or obtusely carinated at the periphery, deeply deflexed an- 

 teriorly, tri-scrobiculate behind the peristome, and with a slight 

 short furrow above the periphery behind the aperture ; aperture 

 subhorizontal, oblong-wedge-shaped ; peristome broadly expanded, 

 brown ; basal margin bearing four equally-spaced teeth within, the 

 outer two united at their bases. Parietal callous elevated at its 

 junction with the upper termination of the peristome. 



Alt. 11-12, diam. 20-22 mill. 



Jamaica. 



H. invalida AD. Contrib. to Conch, no. 5, p. 79. PFR. Monogr. 

 iii, p. 212 ; Conchyl. Cab. p. 447, 1. 153, f. 14-16. REEVE, f. 242. 

 H. candescens AD. Contrib. to Conch, no. 5, p. 80. 



Var. CANDESCENS Ad. 



Lighter colored than the type, the base white ; peristome white. 



An umbilicate specimen is figured (fig. 81), and a three-toothed 

 specimen (fig. 82). 



H. ANOMALA Pfeiffer. PL 37, figs. 61-66. 



Separated from the preceding forms by the extraordinary devel- 

 opment of the peristome, which is in every part free from the preced- 

 ing whorl. 



Broadly umbilicate, depressed, solid, nearly lusterless, dark pur- 

 plish-brown with a narrow white peripheral stripe, all over densely, 

 finely granulate ; spire nearly planorboid or a little convex ; apex 

 polished, generally white; sutures impressed; whorls 4?, convex, 

 slowly widening, the last very deeply descending anteriorly, convex 

 below, constricted behind the peristome by four deep furrows, and a 

 less conspicuous short furrow just above the periphery; aperture 

 subhorizontal, oblong-wedge-shaped, brown within ; peristome light- 

 brown, expanded, produced beyond the expansion and expanded a 



