300 MAZATLAN UNIVALVES 
where it 1s crenated by the ribs, with numerous lamelle, 
undulated, not serrated. 
Hab.—Gallapagos, Cuming.—Sandwich Is. on Pinna, Nuttall.— 
Panama, 16 sp. on stones, near low water mark; C. B. Ad- 
ams.—S. W. Mexico, on Pinna, P. P. C.—St. Vincent 
(Guinea) Sehmidt, teste Menke.—Mazatlan ; extremely rare ; 
L’pool Col. 
Tablet 1474 contains the specimen. 
Genus CAPULUS, Montf. 
Capulus, Conch. Syst. II. 54, 1810.— Phil. Handb. Conch. 
p- 188.— 4. & A. Ad. Gen. i. 371. 
Pileopsis, Lam. Extr. Cours. 1812. 
Amalthea, pars, Schum. Hs. p. 181, 1817. 
351. CapuLUs ——-——, sp. ind. 
Tablet 1475 contains 3 apical fragments which may be con- 
specific, though they differ somewhat in sculpture and outline. 
They appear nearly related to the W. Indian Patella militaris, 
LInnn. The vertex has twa tumid helicoid whirls, of which the 
upper is prominent, in this respect differing from the supposed 
young of Hipponyx serratus. 
Hab.—Mazatlan ; 3 sp. on Spondylus ; L’pool Col. 
Famity VERMETID. 
Neither animals, shells nor opercula in this famity have yet 
been studied by travelers, as much as from their diversity and 
aberrant characters they deserve. The species are extremely 
difficult to discriminate by the shells alone. Habit of growth 
and colour appear to be of more consequence than the variable 
details of sculpture. The figures of Chénu and Valenciennes, 
unaccompanied by either description or geographical informa- 
tion, are rather calculated to confuse than to aid the student. 
Remarkable variations were found among the opercula, which, 
from their occurring among the Spondylus washings, and from 
their not bemg admissible in any other direction, appear to 
belong to this family: but only in regard to two species can 
