HELIX PLAGIOPTYCHA. 23 



Sometimes has a narrow supra-peripheral zone of brown. Allied 

 to H. nemoralina ; but more diaphanous and thinner, more deeply 

 indented in the center of the base, the columellar callus very white. 

 The texture is similar to the thinner species of Fruticicola. 



H. SANTACRUZENSIS Pfeiffer. PI. 11, figs. 18-20 ; pi. 19, fig. 53, 54. 

 Imperforate, depressed, with low-conical or almost planulate 

 spire, solid, whitish (when denuded of cuticle) with or without a nar- 

 row supra-peripheral brown zone ; obliquely striatulate ; whorls 4? 

 to 5, slightly convex, moderately increasing, the last wide, depressed, 

 rounded at the periphery, flattened beneath, and indented around 

 the axis ; abruptly more or less deflected anteriorly, and either reg- 

 ularly rounded or gibbous behind the aperture; aperture broad- 

 lunate, rather auriform, oblique ; peristome sub-labiate, right 

 margin slightly expanded, basal margin widened by an internal 

 callus, rather broad, flat, subhorizontal, inserted in the center of the 

 axis. Alt. 10, diam. 18 mill. ; alt. 9, diam. 21 mill. 



St. Croix. 



H. santacruzensis PFR. MalaL Bl 1855, p. 104, t. 4, f. 4-6 ; and 

 Monographia iv, p. 235. 



The typical form of this species is shown in figs. 18 to 20 of pi. 

 11. It is very variable in shape; the spire often is nearly planor- 

 boid, and the superior lip of the aperture strongly arched. The 

 peripheral fascia is frequently absent ; the young are narrowly um- 

 bilicate and carinate at the periphery. The following species is very 

 closely allied. H. santacruzensis has been found only in a subfossil 

 condition. 



H. PHAEDRA Pfeiffer. PL 12, figs. 56-58 ; pi. 19, figs. 45-47. 



Axis perforated, but covered in fully adult specimens; solid; 

 depressed ; spire low-conical ; straw 'or "Isabella" colored, with or 

 without a narrow, chestnut supra-peripheral fascia ; last whorl not 

 gibbous behind the aperture, rather flattened and deflected there. 

 Upper and lower margins of the peristome slightly and equally 

 curved, subparallel ; upper and outer margins simple, basal margin 

 not thickened within (as H. santacruzensis is,) but its edge reflexed 

 and adnate over the umbilicus and for a short distance on the base. 

 The columella is not flattened or concave on its face as in H. santa- 

 cruzensis. Alt. 10, diam. 21 mill.; alt. 11, diam. 18 mill. 



Pto. Plata and Angostura Arriba, Hayti. 



H.justi PFR. Malak. Blat. 1858, p. 149, t. 3, f. 4-6 ; and Monog- 



