42 MOLLUSCA. 
than H. lirata, and the spiral ridges are said to be alternately weak and strong in 
H. unidentata 38; but the specimens in Pfeiffer’s collection show no remarkable differ- 
ence from H. lirata. Sowerby’s and Reeve’s H. unidentata do not agree at all with 
Pfeiffer’s; they are even somewhat more elevated than their H. lirata. 
H. semistriata is said to be smooth below; but HA. lirata, H. unidentata, and 
H. rusticella are conspicuously glossy and only faintly ridged on the under surface. 
VIL. Dubious Helicine. 
Of small size, with thin straight peristome (/desa, H. & A. Adams): these, perhaps, 
representing only the young state of other species. 
_ Helicina antoni. 
Helicina antoni, Pfr. in Zeitschr. f. Malak. 1848, p. 88°; Martini & Chemnitz, Syst. Conch.-Cab. 
ed. 2, Helicina, no. 55, p. 44, t. 5. figg. 85-38°; Monogr. Pneum. Vivent. i. p. 377°; Gray, 
Cat. Phaneropn. p. 273*; Sow. Thes. Conch. iii. p. 285, t. 270. fig. 181 (male)’; Reeve, 
Conch. Icon. xix., Helicina, t. 19. fig. 165 °. 
Hab. Honpuras °° (Dyson 1? 4). 
Helicina diaphana. 
Helicina diaphana, Pfr. P.Z.S8. 1850, p. 98'; Monogr. Pneum. Vivent. i. p. 384°; Gray, Cat. 
Phaneropn. p. 279°; Sow. Thes. Conch. ili. p. 291, t. 275. fig. 341*; Reeve, Conch. Icon. 
xix., Helicina, t. 28. fig. 251°. 
Hab. Honpuras *° (Dyson ! 23). 
Helicina exigua. 
Helicina exigua, Ptr. P. Z. S. 1848, p. 121°; Monogr. Pneum. Vivent. i. p. 353°; Gray, Cat. 
Phaneropn. p. 255° (nec H. exigua, Homb. & Jacq.). 
Hab. Honpuras (Dyson } 23). 
Helicina microdina. 
Helicina microdina, Morelet, Test. Noviss. ii. p. 18 (1851)’; Pfr. Monogr. Pneum. Vivent. i. 
p. 854°; Gray, Cat. Phaneropn. p. 256°. 
Hab. N. Guatemata: Vera Paz?, common (Morelet ! 2), 
Helicina mohriana. 
Helicina mohriana, Pfr. in Malak. Blatt. viii. p. 172 (1861)'; Monogr. Pneum. Vivent. iii. p. 2197 
Hab. E. Mexico: Orizaba? (Mohr '). 
