205 



stitiis quoque corrngatis ; cyatho (ut in C. spinoso y?<more) 171- 

 completo, duabus marginibus affi,xo, intus planato et angulato ; 

 margine a costis crenulato. 

 Long. -7, lat. -68, alt. -48. 



Hab. Mazatlan {Col. Jeiveit) ; sp. unic. in Mus. Gould. 

 It is hazardous to describe a Calyptrseid from a single specimen. 

 This has the general aspect of C. violascens, with sculpture resem- 

 bling C. imbricatum var. Broderipii, and a cup, which, although the 

 shell has an appearance of normai growth, preserves the incomplete- 

 ness which is characteristic of the genus in its early stage. The 

 yomig statė seems to have been externally likę that of Siphonaria 

 gigas, with few, narrow, projecting ribs. The apex is rubbed. It 

 resembles Calyptrcea striata, Say. 



46. Crepidula explanata, Gould, p. 4. pi. 14. f. 7. 

 Crepidula perforans. Vai. Voy. Ven. Moli. 

 Crepidula exuviata (quasi Nutt.), Jay's Cat. no. 3027. 



This shell, remarkable as is the form of the adult, is normai when 

 young. Specimeus of C. nivea were found in the Mazatlan coUec- 

 tion of similarly distorted form, from living in the holes of Litho- 

 phagi; but they never displayed the cancellations between the 

 laminse which appear in some specimens, but not all, of the present 

 species. The prior name of Valenciennes is rejected, as implying an 

 untruth. 



47. MODULUS DISCULUS, Phil. 



Modulus dorsuosus, Gould, p. 10. pi. 14. f. 12. 



48. FossARUs (IsAPis) ovoiDETJS, Gould. 

 Narica ovoidea, Gould, p. 7. pi. 14. f. 10. 



Comp. Fossar reticulatus, A. Ad. ; vide B.M. Maz. Cat. in loco. 

 Hab. 1 Mazatlan (^Col. Jevoett). Mus. Gould. 



49. ?Lacuna tjnifasciata, n. s. 



? i. t. parva, solida, conica, ad basin angulata ; anfr. v. leevibus, 

 parutn convezis, sutura distincta ; rufo-fusca, linea intensiore 

 ad carinatn sutura convenientem, interdum maculis adjacen- 

 tibus ; rimą umbilicali a labio subcelata ; apertura ovali ; 

 apice regidan. 



Long. -23, long. spir. "ll, lat. '15, alt. '45°. 



Hab. Sta. Barbara {Col. Jewett). Mus. Gould. 



This shell has the shape of Littorina angulifera, the general 

 aspect of the small Phasianellee, and the chink of Lacuna. Its 

 operculum is unknown, all the specimens in Mus. Gould being dead. 



50. Cerithidea albonodosa, n. s. 



C. t. solida, C. varicosse simili, compacta, fusco-purpurea, va- 

 ricibus et nodulis albis, fasciis spiralibus intensioribus stepe 

 ornata ; anfr. xii. parum convexis, sutura impressa ; liris 

 spiralibus iv. in anfr. penult. et liris creberrimis transversis 

 vix undatis, ad intersectiones nodosis, ornata ; varicibus iii. in 



