336 MAZATL^N 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. mediokeve, 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. Long. 1'04, 

 long. spir. '7, lat. '45, div. 35. 

 Hob. PTaboga; 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 imm'ature 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. uncihatum ; 

 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. CEBITHIUM , sp. ind. (a) 



Tablet 1590 contains a young sp. (and an imperfect one 

 much younger,) measuring '44 by '22, resembling the shell on 

 tablet 1589 in the general style of sculpture, but without the 

 medial 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 striae over the whole surface. 

 It may possibly be a variety of C. famelicum. 



Hob. Mazatlan ; 2 sp. young ; L'pool Col. 



385. CEEITHIUM ALBOLIRATUM, n. s. 



C. t. conicd, turritd, alba ; anfractibus c&mpactis, plus 

 minusve subconvexis ; liris spiralibus valde expressis cinctd ; 

 iii. v. in spird monstrantibus, quarum una vel duo interdum 

 majores ; costas transversas, undulatas, subobsoletas superanti- 

 biis ; aperturd subquadratd. 



The sculpture consists of fine spiral bars with well defined 

 interstices traveling over obscure transverse ridges, which do 



