GASTEROPODA PECTfNIBRANCHIATA. ^ffi 



and widened in its anterior portion, which is distinguished by two 

 deep emirginations. The eyes are on the sides of the tentacula, and 

 near their base. It has neitlier veil nor operculum*. The 



PuiiPURA, Brug. 



Is known by its flattened columella, which is trenchant near the end 

 opposite to the spire, and which, with the external margin, forms a 

 canal there, sunk in the shell, but not salient. The Purjjui'oe were 

 scattered among the Buccina and the Murices of Linn;i.-us. The ani- 

 mal resembles th it of a true Buccinumf . 



The genus Licorne, Montf., — Monoceeo?, Lim., consists of shells 

 similar to the Purpuric, but in which the external edge of the emar- 

 gination is furnished with a salient spinet. 



Others, also resembling the Purpuric, in which the columella or 

 at least the margin is provided, in the adult, with teeth which narrow 

 the aperture, form the Sistra, Montf, or the Ricinula, L.un.§ 



CoNCHOLEPAs, Lam. 

 The general characters of the Purpurre, but the aperture is so 

 enormous, and the spire so small, that the shell has almost the appear- 

 ance of a Capidus, or one of the valves of the Area ; a small salient 

 tooth is visible on each side of the emargination. The animal re- 

 sembles that of a true Buccinum, with the exception of its foot, which 

 is enormous in widtli and thickness, and that it is attached to the shell 

 by a muscle shaped like a horse-shoe, as in the Capuli ; it lias a thin, 

 narrow, and horny operculum. 



But a single species is known, the Buccinum conckolepas, 

 Brug.; Argenv., pi. ii, f. F, D; and Sowerb., Gen. of Shells, 

 No. VI. From the coast of Peru. 



Casis, Brug. 



The shell oval ; aperture oblong or narrow ; the columella covered 

 with a plate as in Nassa, and that plate transversely plicated, as well 

 as the external margin ; the emargination terminating in a short 

 canal, that is reflected and pushed b.ick, as it were, to the left: 

 varices are frequently observed on it. The animal resembles that of 

 a true Buccinum, but its horny operculum is denticulated, in order 

 to pass between the plicae of the external margin. 



* Buecinutn harpci, L., and the other species long confounded with it — List., 992, 

 993, 994 ; Mart., TIF, cxix: Bucc. costatum, lb. Messrs. Reynaud, Quoy and 

 Gaymard have ohscrved, that, under certain circumstances, the posterior part of the 

 foot is spontaneously detached. 



■j- Buccinum persicnm, List., 987, 46, 47 ; — B. patulum, Id., 989, 49 ; — B. hee- 

 mastoma, Id., 9SS, 48 ; — B. trochlea, B. lapillus, Id., 965, 18, 19 ; — Mnrex fucits. 

 Id. 990, 50 ; — Mur. hisfi-Lv, Martini, III, ci, 974, 975 ; — Mur. martcindlu., List., 

 95f), 8, 957, 9 — 10 ; — Mur. hippocastanum, List., 955, 996, 990, 991. 



X Buccinum monodon, Gni., Martini, III, Ixix, 761 ; — Bucc. narcal, Brug. ; — B. 

 unicorne, Id. 



§ Murcx ricinis, L., Seh., Ill, Ix, 37, 39, 42; — Mur. neritotdeus, Gm., No. 43, 

 lAst., 804, 12—13. 



