O&CUM. 215 



Genus CAECUM, Fleming, 1817. 

 Section I. Levia. 



C. L^VE, C. B. Ad. PL 66, fig. 52. 



Shell rather obese, short, smooth, shining, subdiaphanous, 

 tinged with brown, slightly contracted in front, the aperture 

 oblique ; operculum concave. Length, '07 inch. 



Panama to Mazatlan. 



Folin has described vars. subornatum and cylindrica. The 

 figure is from a specimen identified by P. P. Carpenter. 



C. FARCTMEN, Cpr. PI. 66, fig. 53. 



Like C. Ixve, but whitish, aperture less contracted, more slen- 

 der, septum submucronate ; operculum with a spiral marginal 

 rib. Length, *064 inch. Mazatlan. 



C. VITREUM, Cpr. PL 66, fig. 54. 



Subelongate, vitreous, shining, a little tumid towards the 

 oblique aperture, septum prominent, mucronate. 



Length, -073--107 inch. Teneriffe ; Mediterranean Sea. 



G. Sardinianum,o\in, and (7.<5^a&ri/7n,McAndrew,aresynonyms. 



Var. CLARKTI, Carp. PL 66, fig. 55. 



Shell smaller, straighter, septum ungulate, apex more obtuse. 



Teneriffe. 

 C. DEXTROVERSUM, Carp. PL 66, fig. 56. 



Narrow, rather elongated, thin, septum tumid, submamillated, 

 operculum concave. Length, *092 inch. Mazatlan. 



The specimen figured is a junior. 



Yar. ANTILLARUM, Carp. 



A single young specimen was found in W. Indian sponge, not 

 presenting any characters by which it can be separated from C. 

 dextroversum. Why should it be designated by a varietal name ? 



C. GLABRUM, Mont. PL 66, fig. 57. 



Shell narrow, thin, smooth, subdiaphanous, aperture not con- 

 tracted, nor tumid, white, septum without appendage. 



Length, -68 inch. Atlantic Coast of Europe. 



The operculum is externally convex, constituting it the type 

 of Gray's group Brochina. The synonyms include Dentalium 

 minutum, Linn. ; Brochus laevis, Brown ; Cornuoides minor, 

 Brown (juvenile); Odontidium levissimum, Cantr. ; Brochus 

 arcuatus, Brown ; Vermiculum incur vatum, Mont. 



