HELICINID A. 239 
mella very short, arcuate, scarcely dilated above; peristome 
simple, slightly expanded. Height 33, greatest breadth 4, 
least br. 3? mill. 
Trochatella elegantula, Pfr. in Z. f. If, 1850, p. 76; Ic. t. 10, 
f. 28-31 ; Pnewm. Mon. p. 332. 
Hab. St. Domingo (Sallé). 
9. TROCHATELLA TENUIS. 
Shell minute, pyramidate, thin, slightly decussated (under a lens), 
with rather crowded spiral lines and irregular strize of growth, 
diaphanous, fuscous ; spire conic, rather stair-shaped ; whorls 43, 
flat, the two last ones slightly keeled; aperture very oblique, 
roundish-lunate; columella very shortly arcuate; peristome 
simple, straight, sharp. Operculum membranaceous, fulvous. 
Height 2, greatest breadth 23, least br. 2} mill. 
Helicina tenuis, Adams, Contrib. to Conchol. n. 1, p. 14. 
Trochatella tenuis, Adams, Catal. 1849 et 1851; Pfr. Pneum. 
Mon. p. 332. 
Hab. Jamaica. 
10. TRocHATELLA RUPESTRIS. 
Shell pyramidate, thin, spirally striated, not shining, lemon- 
yellow or brownish-red; whorls 5, flat, somewhat disjoined, the 
last ones slightly keeled, last slightly descending, rather convex 
beneath; aperture entire, ovate, somewhat quadrangular, co- 
lumella short, perpendicular; peristome simple, sharp. Oper- 
culum very thin, pale yellow. Height 38, greatest breadth 4, 
least br. 33 mill. 
Helicina rupestris, Pfr. in Wiegm. Arch. f. Nat. 1839, i. p. 355; 
Sow. Thes. n. 46, p. 10, t. 3, f. 120. 
Trochatella rupestris, Pfr. in Z. f. M. 1848, p. 82; Ic. n. 7, p. 8, 
t. 5, f. 12-15; Pnewm. Mon. p. 333. 
Hab, Cuba (on the banks of the river Yumuri, near Matanzas). 
§ 4. Shell distinctly heeled. 
11. TrocHATELLA TANKERVILLII. B. M. 
Shell top-shaped, rather solid, obliquely striated and girdled with 
close-set granulated ridges, whitish-yellow, with two series of 
red spots; spire conic, pointed; whorls 63, flat, the last one 
moderately convex beneath, acutely keeled at the periphery ; 
keel strongly crenate; aperture rather triangular, white and 
shining within; columella flat, shortly receding, forming a 
right angle with the basal margin; peristome broadly ex- 
panded, waved, with the margins joined by a very thin callus. 
