28 HELIX HEMITROCHUS. 



VAR. CALACALOIDES Pilsbry. PI. 31, figs. 24-26. 



Conical ; umbilicus as in H. varians and H. gallopavonis ; peris- 

 tome labiate, expanded, pink ; color, white, of a chalky texture, 

 scarcely shining ; bands when present, whitish brown ; last whorl 

 much more rapidly widening than that of H. gallopavonis. Incre- 

 mental lines rather irregular, just as in H. gallopavonis, not so 

 strong as in H. troscheli ; columellar lip concave ; not straightened 

 as in H. calacala. Apex pink or white. Alt. 13, diam. 15-> mill. 



Ambergris Cay. Turk's Id. group. 

 H. TROSCHELI Pfeiffer. PL 13, figs. 64-67 ; PL 20, figs. 59-64. 



A form allied to H. gallopavonis in texture, form and coloration, 

 but more strongly striate, and having a decidedly more broadly ex- 

 panded peristome with a stronger thickened rib within. 



Perforate, depressed conico-globose, rather thin, opaque, painted 

 in innumerable patterns with chestnut, yellowish, deep' brown or 

 pinkish-brown spiral bands or longitudinal streaks or unicolored, 

 the apex generally pinkish. Surface costulate striate, shining; 

 spire elevated or depressed, apex minute, slightly obtuse, smooth ; 

 sutures impressed ; whorls 4J to 5, slightly convex, the last wide, 

 depressed, often obsoletely carinated in front of the aperture, rather 

 deeply deflexed anteriorly, slightly constricted behind the basal part 

 of the peristome ; aperture rounded-lunar, quite oblique, showing 

 the bands within ; peristome brown, pink or white, strengthened by 

 a strong rib within ; its margins converging ; outer and basal mar- 

 gins rather broadly expanded ; baso-columellar margin more oblique 

 than in H. gallopavonis, less concave, generally somewhat straight- 

 ened, more thickened within, sometimes with a tiny notch or trunca- 

 tion at the base of the columellar callus ; at its insertion the lip is 

 reflexed over and partly conceals the umbilicus, which is generally 

 wider than in H. gallopavonis. The parietal wall and aperture gen- 

 erally is not so deeply stained with pink as in H. varians, etc. 

 Measurements of four specimens are as follows : 



Alt. 12, diam. 16 mill ; Alt. 12, diam. 14 mill. ; Alt 10, diam. 

 15 mill.; Alt. 9, diam. 11 mill. 



New Providence, Bahamas. 



H. troscheli PFR. Symbols iii, p. 76, (1846) ; Conchyl. Cab. p. 222, 

 1. 109, f. 6-11 .REEVE, f. 289. H. calacala WEINL. Jahrb. d. mal 

 Gesell, vii, 1880, p. 374, t. 12, f. 21. H. tenuicostata DUNKER, in 

 PHILIPPI, Abbild., ii, p. 32, t. 6, f. 13. PFR. in Conchyl. Cab. t. 109, 

 f. 14, 15 ; Monogr. i, p. 335. REEVE, f. 1224. CROSSE ET FISCHER, 

 Moll. Hex. et FAmer. Cent., p. 298. 



