276 CERION, GROUP XIII. 



C. DALLI (Maynard). PL 45, figs. 99, 1, 2, 3, 4. 



Shell rather large, solid, shortly rimate, cylindric ; flesh-tinted, 

 with white riblets, or nearly white. Whorls about 11^, but slightly 

 convex. Sculpture of close, fine, white riblets, typically fifty or more 

 on the penultimate whorl, but varying within wide limits. Aperture 

 truncate-ovate, dark purplish-brown within, the peristome white or 

 brown, reflexed and thickened, the margins continuous by a strong 

 parietal ledge. Parietal lamella rather low and deeply placed, con- 

 tinuous within with a long spiral lamella which extends inward 

 about 1^ whorls ; the almost equally long infra-parietal lamella 

 parallel with it, and usually nearer than in O. rubicundum. Axial 

 lamella inconspicuous from in front. 



Length 22, diam. lg mill. 



Length 31^, diam. 11 mill. 



Length 33, diam. 121 m in. 



Length 36, diam. 11^ mill. Inagua. 



Strophia dalli MAYNARD. Contrib. to Science i, p. 128, 129, 135, 

 f. 32, 33, pi. 13, f. 23 (October, 1889). 



Larger than 0. rubicundum. Typically with more numerous 

 riblets and longer parietal lamellae ; but the large series before me 

 shows such great variation that it is likely that specimens will be 

 found intermediate between the two species. 



Some specimens are nearly white, the intervals being only faintly 

 tinted, and the aperture is yellowish-brown within. Others have a 

 few stripes of rusty brown. In one lot of large specimens the macu- 

 lation is like that of G. marmoratum, and the riblets vary from 27 to 

 56 on the penultimate whorl. The most finely ribbed shell before 

 me has 73 rib-striae on the penultimate whorl. 



One specimen, among a large number opened, has no entering 

 lamellae behind the well developed but short parietal lamella, being 

 a " Maynardia " in the teeth, while it has all other characters of the 

 C. dalli with which it occurred. It is a fresh shell, quite unworn 

 inside. 



C. DUPLODON Pilsbry & Vanatta. PI. 45, fig. 95. 



Shell shortly rimate, rather thin, cylindrical, the latter three 

 whorls of about equal diameter, those above slowly tapering to form 

 a rather long, convex cone. White, variegated with gray-white. 

 Whorls 10^, slightly convex, two nepionic smooth, those of the cone 



