CERION, GROUP VIII. 2?7 



(1878); Proc. Acad. Nat. Sci. Phila. 1874, p. 53, pi. 8, f. 1 (denti- 

 tion); Ann. N. Y. Acad. Sci. iii, p. 100, pi. 7, f. A. Cerion 

 (Strophiops) decumanum Fer., DALL, Bull. Mus. Comp. Zool. xxv, 

 no. 8, pp. 122, 124, fig. 4. 



Not Papa decumana Fer., PFR., Monogr. Hel. Viv. ii, p. 320, 

 1848 (except references to Sowerby and Reeve), nor of GRAY, Ann. 

 of Philos. (New Ser.) 1825, xi, p. 413 (no description ; referring to 

 Lister, pi. 588, f. 47, a species resembling multicosta). 



The largest species of the genus. It is closely allied to C. wein- 

 landii from which it differs in the large size, snowy whiteness and 

 the broader area behind the columellar lip. 



Benson's original description is given above. The shells are 

 usually more cylindrical than his type (pi. 35, f. 22, 23); very solid, 

 snow-white, the throat generally tawny. The last whorl is more or 

 less plicate dorsally. The parietal lamella is long, making about 

 one fifth of a spiral turn. The axial lamella generally ascends 

 nearly 3 whorls. Size varies within wide limits, as follows : 



Length 46^, diam. 17, long axis of aperture 19J mill.; whorls 11. 



Length 45, diam. 15, long axis of aperture 18 mill.; whorls 11. 



Length 37, diam. 15, long axis of aperture 15^ mill.; whorls 10. 



Length 34, diam. 14^, long axis of aperture 15 mill.; whorls 9^. 



Crosse has attempted to revive the name decumana for this species, 

 showing that the specimens in Ferussac's cabinet were identical with 

 regia Bens.; but P. decumana was in no way defined by Ferussac, 

 and was introduced by Gray in 1825 for a shell resembling \nulh- 

 costa, this interpretation of the species being followed by Pfeiffer in 

 his earlier description. The course taken by Crosse was therefore 

 clearly inadmissible. 



PI. 35, figs. 22, 23, are copies of Kiister's figures of Benson's type 

 pecimen. Fig. 24 is Sowerby's "P. mumia" a broader shell than 

 any I have seen. Figures 17-21 are from Castle Island specimens 

 in the collection of the Academy. 



C. WEINLANDI ( k Kurr* Martens). PI. 37, figs. 54, 55, 56, 57. 



Shell deeply and openly rimate, often perforate, cylindric, solid, 

 white or flesh-colored, nearly smooth. Whorls 9J to 10, nearly flat, 

 marked with slight growth-wrinkles, the last often irregularly plicate 

 liHiind the aperture, compressed and obtusely keeled below; last 3 

 or 4 whorls of about equal diameter, those above forming a short 



