22 HELIX PLAGIOPTYCHA. 



H. NEMORALTNA Petit. PI. 11, figS. 9. 



Imperforate, depressed, thin but rather strong, whitish brown or 

 yellowish, sometimes rose-tinted, with a supra-peripheral narrow 

 dark brown fascia, bordered below by opaque white ; surface very 

 finely striate, nearly smooth, shining ; spire low-conical, apex obtuse ; 

 whorls 4, slightly convex, the inner ones colored like the last or 

 more rosy, rapidly increasing, the last rounded, depressed, briefly 

 descending anteriorly ; aperture oblique, truncate-oblong ; peristome 

 simple above, narrowly expanded on the outer margin ; upper and 

 lower margins subparallel, not converging ; baso-columellar margin 

 adnate to the base, widened toward the insertion, with a flat pink 

 face, rarely white ; inner edge with a low median fold ; parietal 

 callus very thin or wanting. Alt. 7-9, diam. 14 mill. 



St. Thomas, St. Johns, Tortola, Virgin Is. ; Hayti. 



H. nemoralina PETIT, Guerins Mag. de Zool. 1836, t. 80. FER, 

 Hist., t. 29A, f. 1-3. PFR. in Conchyl. Cab. t. 72, f. 19-21 and 

 Monogr. i, p. 281. REEVE, Conch. Icon. f. 293. 



A well-marked from, allied to H. monodonta, but not strongly 

 toothed on the basal lip, the margins of the peristome scarcely at 

 all converging, and pink in color. The brown band is sometimes 

 replaced by opaque white. 

 Var. INTENSA Pilsbry. PI. 31, figs. 6, 7. 



Shell more solid; opaque, whitish, tinged with purplish; upper 

 whorls and apex deep purplish ; last whorl deeply deflexed anterior- 

 ly ; aperture smaller than in the type, peristome thickened within, 

 deep pink. Alt. 9, diam. 14 mill. 

 H. DIAPHANA (Lamarck) Pfr. PL 11, fig. 8 ; pi. 19 figs. 51, 52. 



Imperforate, globose-depressed, thin, translucent; light greenish 

 yellow, smooth, shining, slightly marked by growth-lines ; spire low- 

 conical, a little obtuse ; sutures but slightly inf^ressed ; whorls 4, 

 slightly convex, the last wide, rounded, depressed, only slightly 

 descending anteriorly, very deeply indented in the center of the base, 

 forming a sort of "false-umbilicus" which is lined with a white 

 deposit reflected from the columella. Aperture oblique, broadly 

 lunar ; peristome thin, very narrowly expanded on the outer and 

 basal margins ; columella nearly straight, oblique, thin, white, deep- 

 ly inserted in the center of the axis. Alt. 9, diam. 14 mill. 



Porto Rico ; Vieque. 



H. diaphana (LAM. An. s. Vert, vi, p. 85. ?) PFEIFFER, Monog- 

 raphia, i, p. 281; iii, p. 148 Conchyl. Cab. p. 45. CHENU, Illust. 

 Conchyl. iii, t. 8, f. 14. REEVE, Conch. Icon. f. 1312. 



