(LECUM. 215 



Genus CAECUM, Fleming, 1817. 



Section I. Levia. 

 C. IJEVE, 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. FARCIMEN, Cpr. PI. 66, fig. 53. 



Like C. l&ve, 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, Folin, and 0.gra&rwm,McAndrew,aresynonyms. 

 Var. CLARKTT, 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 G. 

 dextr over sum. 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 external^ 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. ; ftrochus 

 arcuatus, Brown ; Vermiculum incuruatum, Mont. 



