338 MAZATLAN UNIVALVES 
the different development of the tubercles on the same whiul, 
the axis has occasionally a bent appearance. Gould’s type 
appears to have been rubbed smooth and faded. The opercu- 
lum is not large for the shell, and closely resembles that of 
C. maculosum. The nucleus however is not sunken; the 
surface is not minutely striated, the outer margin is irregularly 
indented, and the markings of the muscular scar are coarser. 
The upper whirls are few in proportion, with the same diver- 
gence as the adult. Long. 1°4, long. spir. °8, lat. °66, div. 40°. 
Hab.—Acapulco, Humboldt & Bonpland.—Panama & Taboga ; 
at and above half tide level ; mostly in the margin of water 
left in the rocks by the tide; very common, C. B. Adams.— 
Gulf of California and Galapagos, Sowerby, (Mus. Cuming.)— 
S. W. Mexico, P. P. C—Mazatlan; abundant; LZ’pool Col. 
Tablet 1593 contains 7 sp. different ages, elongated.—1594, 
8 sp. do. broader.—1595, 3. sp. adult; of which one (dead) has 
marine attachments.—1i596, 2 sp. lob-sided.—1597, 2 do. pale 
state.—1598, 1 sp. with operculum.—1599, 1 sp. with mended 
fracture.—1600, 2 sp., one with Balanus, the other bored by a 
Proboscidean ; extremely rare.—1601, 9 opercula. 
388. CERITHIUM INTERRUETUM, Mke. 
Cerithium interruptum, ‘fhe. in Zeit f. Mal. 1850, p. 178, 
no. 41.—C. B. Ad. Pan. Shells, no. 198, p. 153.—(Non 
Cerithium interruptum, Lam. An. s. Vert. vol. ix. p. 328, 
no. 1. Fos. Grignon.)* 
? + Cerithium ———,, sp. ind. ©. B. Ad. lo 
Comp. Cerithium (Tympanotonns) Galapa 
e. cit. no. 199. 
cinis, A. Ad. in Sow. 
Thes. Conch. p. 869, no. 85, pl. 182, 
This species agrees exactly with both the figure and the 
diagnosis of C. Galapaginis, but that shell is classed with Tym- 
panotonus, with which this has no connection. It begins with 
three smooth whirls, which soon fall off: then a few in which 
the sculpture is wholly in spiral lire, of which one just above 
the suture is stronger, angulatinge the periphery ; at this stage 
the base is scarcely notehed, and the shell closely resembles 
Trichotropis : afterwards the angular ridge subsides, the spiral 
lines become granulose and the whirls somewhat rounded. 
® Should this imperfectly characterized shell prove to belong to the same genus, 
Menke’s name must be altered. If C, Galapaginis be identical, that may be 
retained. If not, it may, according to custom, take the name of C, Menkei. 
