348 



SHELLS AND SHELL-FISH. 



Shell turbinate, mostly trochiform*, the substance almost 

 always perlaceous ; outer lip never thickened ; aperture 

 entire, closed by a shelly or horny operculum. 



SuB-FAM. SENECTIN^. Snake Shells. 



Operculum round ; calcareous ; shell turbinate ; the 

 basal whorl ventricose ; pillar always smooth ; aperture 

 round, rarely oblique. 



^ENECTvs Humph. Imperforate; the base 

 produced into a broad flat lobe ; spire 

 rather elevated and pointed ; the 

 whorls convex ; aperture perfectly 

 round ; not more oblique than Helix ; 

 inner lip entirely wanting. (Jig. 110.) 



imperialis. Mart. 1 80. f. 1^90. 

 marmoratus. E. M. 448. f. 1. 

 pethiolatus. Mart. f. 1777-8. 

 cornutus. lb. 179. f. 1779-80. 

 setosus. En. Meth. 448. f. 4. 

 argyrostomus. Mart. f. 1766. 

 chrysostomus. lb. f. 1766. 



radiatus. Mart, f, 1788-9. 

 margaritaceus. lb. f. 1762. 

 Sprenglerianus. lb. f. 1801-2. 

 crenulatus. lb. f. 1811-12. 

 hippocastanum. lb. f. 1807-10 

 coronatus. En. M. 448. f. 2. 

 angulatus Sw. Sow. Gen, f. 8. 



Marmarostoma Sw. Umbilicus deep ; spire of few 

 whorls, much depressed, and obtuse ; inner lip ob- 

 solete ; base even more produced than in Senectus, 

 but never distinctly channeled. 



M. versicolor. Mart. 176. undulata. Chem. 169. f. 

 f. 1740, 1741. 1640, 1641. 



Delphinula Lam. Turbinate ; spire depressed, the tip 

 obtuse j pillar almost entirely wanting ; the umbili- 

 cus being large and pervious ; exterior of the shell 

 rough with tubercles or lamellar plates, (^fig. IO9. ^O 

 torquata. Mart. Conch.2.f.71. laciniata. En. Meth. 451. 

 lamellosa. Zool. J. v. p. 33 1 . f. 1 . 



CYCLOCANTHAt Sw. Sub- depressed, trochiform; im- 



* Except Phasianella. 



t Resembles Tubicanthus, but the aperture is hardly perlaceous, the 

 body-whorl not flattened beneath, or the mouth oblique. 



