330 MAZATLAN UNIVALVES 
the other just below the periphery, so as not to be seen in the 
spire ; and another, smaller still, round the base. The labrum 
is distinctly three-cornered between the canals; anterior canal 
not quite so long as in C. f. medioleve, and rather more curved ; 
surface less glossy; shape less slender. Only four perfect 
specimens were found, but fragments and young shells appear- 
ed in the Spondylus washings. The young resembles the adult, 
but with the tubercles semicostal. One of the specimens from 
S. W. Mexico is of a prevailing blackish brown. Jong. 1°04, 
long. spir. °7, lat. °45, div. 35°. 
Habh.—?Taboga; very rare; C. B. Adams.--S. W. Mexico: 
do. P. P. C.—Mazatlan ; extremely rare; L’pool Col. 
Tablet 1588 contains 2 very young specimens, 1 adolescent. 
and 1 adult. 
Tablet 1589 contains an immature specimen, which comes 
nearer to this species than to any other. It has the general 
aspect of C. maculosum, but is not like the young of that 
species. The upper whirls resemble those of C. uncinatum: 
but on the last whirl the tubercles are almost wholly obsolete, 
and the surface generally is granulose. The aperture also is 
much longer in proportion. Long. °65, long. spir. °38, lat. *29. 
384, CERITHIUM ———, sp. ind. (a) 
Tablet 1590 contains a young sp. (and an imperfect one 
zauch younger,) measuring ‘44 by *22, resembling the shell on 
tablet 1589 in the general style of sculpture, but without the 
redial tubercles on the upper whirls, and with the canal long 
and straight. It has faint semi-costal tubercles below the 
suture, and finely granulous spiral strie over the whole surface. 
It may possibly be a variety of C. famelicum. 
Hab.—Mazatlan ; 2 sp. young; L’pool Col. 
385. CERITHIUM ALBOLIRATUM, 2. s. 
C. t. conicd, turritd, albé ; anfractibus compactis, plus 
minusve subconvexis ; liris spiralibus valde expressis cinctéd ; 
il.—yv.in spird monstrantibus, quarwm una vel duo interdum 
majores ; costas transversas, undulatas, subobsoletas superanti- 
bus; aperturé subquadratd. ‘ 
The sculpture consists of fine spiral bars with well defined 
interstices traveling over obscure transverse ridges, which do 
