MAZATLAN UNIVALVES abd. 
Bees Pu 
Comp. C. sacrata, Gould, Hap. Shells, p. 60: (=C. Californica, 
Nutt. ms.—Var.=C. fuseata, Gould ms. teste Nutt.) Hab.— 
Upper California. 
Comp. Cerithium (Potamides) Hegewischu, Phil. in Zeit. f. 
Mal. 1848, p. 19, no. 81. (Hab.— Mexico, ? ubi.) 
Desh. & C. B. Ad. both doubt the identity of Sow.’s and 
Kien.’s species. The Mazatlan shells scarcely accord with 
either, and may prove distinct. The genus is not yet well 
understood. Sow. unites to this Pzl.’s species, which is pro- 
bably an allied form from the West Indies; also C. iostoma, 
Pfr. (2ubi); also C. helicoide, ‘‘the narrow variety without 
varices,” OC. B. Ad. (Pubi); as well as (rightly) C. validum, 
C. B. Ad. “Shells of Jamaica.”* 
The Mazatlan species scarcely agrees with the S. American 
shells in D’Orbigny’s collection ; and have much more the 
appearance of the variable Californian species, C. sacrata, 
which however has much fainter spiral and stronger transverse 
sculpture. It most closely resembles a W. Indian species, 
which is probably that intended by Philippi, but differs in its 
uniform dark colour. The scarcely varicose forms are known 
at once from the dwarf variety of C. Montagnei by the strong 
spiral sculpture, even on the upper whirls, the subquadrate 
aperture, and the absence of thick labial deposit. The surface 
is scarcely corrugate ; epidermis rather thick, rough and 
deciduous. ‘The operculum closely resembles that of C. Mon- 
tagnei, but is slightly less concave, and somewhat larger in 
proportion. Occasionally cup-shaped bodies are found on it, 
which look like the remains of egg-cases. It generally measures 
about °95 by °35; an extraordinarily large one measures 
long. 1°36, long. spir. 1°04, lat. (sine var.) °46, div. 20°. 
Tablet 1628 contains 5 sp. in various stages of growth.—1629, 
3 do. intervarical state.—1630, 4, do. solid, hg¢ht mouth.—1631, 
3 do. form more elevated.—1632. 5 normal state.—1633, 5 do. 
varices strongly developed —1634, 3 do. varices scarcely deve- 
loped.—1635, 2 sp. varying in sculpture.—1636, 2 do. mended 
after fracture.—1637, 1 sp. with operculum in situ; and 3 
separate opercula, one of which is scarcely spiral (?through 
accident). 
* The inaccuracy with which the labours of Prof. Adams are quoted or ignored 
by Mr. Sowerby, jun. may be co-ordinate with the execution of the remainder of 
the Monograph, but scarcely does justice to the honoured name which the author 
inherits. 
