986 MAZATLAN UNIVALVES — 
adult state, should be so different in their early stage, is very 
remarkable. A series of specimens from the inside of a West 
African Pinna, of which the youngest is only ‘04 long, agree 
exactly with the Mazatlan specimens now described. The 
largest, 1°18 in length, would certainly have been called C. 
squama if from Panama, though the epidermis is thinner than 
in the ordinary Mazatlan specimens. ‘They go through the same 
changes of colour, deck margin, &c. as C. nivea; and if they 
had been born in an empty Cowry would probably have deve- 
loped into the genuine C.‘unguiformis. As it is, they are 
probably the C. Goreensis,* a species which, according to 
Dillwyn, has a tendency (like C. nivea) to develop foliations. 
Whether the specimens quoted by Menke as C. Goreensis 
belong to this species or to C. squama, cannot be told without an 
examination of the vertex. Shells of exactly the same species, 
some extremely young and well formed, others of the true C. 
unguiformis shape, circular and elongated, were found in dead 
East Indian Cowries from Singapore The species may abound 
at Mazatlan; but as almost all the vast numbers of shells sent 
were perfectly fresh, there is no knowing what the dead ones 
contained. The largest Mazatlan shell with the apex perfect 
measures long. ‘12, lat. °08, alt. °02. Others, which have lost 
the apex in growth, may belong either to this species or to 
C. nivea. ‘ 
Hab.— Mediterranean, Africa, Singapore, North and South 
America, East and West ; fossil in tertiary strata; v. swpra.— 
Callao, Peru, very fine, in dead shells, B. M. Col. D’ Orbigny, 
not in Cat.—Mazatlan; extremely rare, in dead shells, &c. ; 
L’pool Col. 
-Tablet 1430 contains 3 sp. young.—1431, an adult sp. in 
empty Trivia radians. 
Genus CRUCIBULUM, Schum. 
Crucibulum, Schum. Ess. no. 8, 1817 :—Gray, Proc. Zool. Soc. 
1847, p. 157, no. 270:—H. & A. Ad. Gen. vol. 1. p. 365. 
Dispotza, Say, Journ. Ac. N. 8. Phil. vol. iv. 1124. 
Calypeopsis, Lesson, 1830, Brod. 1834. 
* The young of Cr. fornicata, as appears from specimens from Staten Island 
in the collection of R. M’ Andrew, Esq. is of the type Cr. Goreensis, Gmel. but 
with only one large tumid whirl (as in Crucibulum imbricatum,) lying imbedded 
in the normal portion. Inside with first deck at an angle with the succeeding. 
