H. Doc. 129. 



arated by a deep suture. Aperture elliptical, broadly rounded poste- 

 riorly; lip simple, copiously incrusting the pillar margin, which is 

 profoundly arcuate; umbilical region nearly perforate. 



Length one-eighth of an inch, breadth one-tenth of an inch. 



Found in the Colorado desert. 



In form it is much like A. Cincinnatiensls, Haldeman. or like A. 

 galbana. 



II. MARINE SHELLS FROM THE COAST. 



POTAMIS PULLATUS, Gould. 



Testa turrita. gracilis, solida, rudis furco-cinerea; anfract, ad 10 

 convexiusculis, plicis cerciter 10 convexiusculis, arcuatis compressis 

 instructis, et filis ad 5 volventibus cinctis; tribus ultimis varice 

 munitis: apertura parva, subcircularis, nitide rufo-nigra; basi vix 

 effuso et contorto ; labro expanse. PI. , fig. . 



Shell elongated, turreted, slender, solid, rough, and dusky, com- 

 posed of ten closely revolving moderately convex whorls, ornamented 

 with about 16 longitudinal curved, compressed folds, and about five 

 revolving threads, which usually form beads where they crown the 

 folds; the three anterior whorls are fortified with a strong varix, 

 about two-thirds of a volution distant from each other. Aperture 

 small, nearly circular, slightly produced and contorted at base, very 

 dark and glossy liver-brown within ; lip roundly overted. 



Length 1^ inch, breadth two-fifths of an inch. 



Locality. Brought from San Diego by Dr. Tho. H. Webb and 

 Wm. P. Blake. 



This shell is apparently very common, and yet I find no description 

 answering to it. From P. sacratum, Gould, it may be distinguished 

 by its small and dark colored aperture, and the longitudinal folds. 

 It is much like P. iostoma, Pfeitter, a Cuban species. Some of the 

 specimens are very much more slender than others. 



PHASIANELLA COMPTA, Gould. 



Testa parva, solida, ovato-conica, imperforata, polita, cinerascens, 

 lineis minutis oblique volventibus olivaceis ornata; spira acuta; an- 

 fractibus quatuor rotundatis; ultimo ad peripheriam obtuse angulato, 

 et interdum tessellatem fasciato : apertura circularis; labro tenui, alvo; 

 columella alba, compressa; faucibus callo albo incrassatis. PI. , 

 fig.. 



Shell small, solid, ovate, imperforate, smooth and shining, ashy 

 white, minutely and closely lineated in an obliquely spiral manner 

 with olive green. Whorls four, well rounded, forming an acute spire, 

 the outer one obstusely angular at periphery, where there is some- 

 times a delicate catenated range of white and olive spots, aperture 

 nearly circular; lip very thin, showing the lineations on the inner 

 margin; throat coated with bluish white enamel; pillar flattened; 

 white. Operculuni patelliform, ivory-like, the outer convex surface 

 marbled black and white; the inner surface black. PI. , fig. . 



Length one-fourth of an inch; diameter one-fifth of an inch. 



