GASTEROPODA PECTINIBRANCHIATA, 
71 
and widened in its anterior portion, which is distinguished by two 
deep emarginations. The eyes are on the sides of the tentacula, and 
near their base. It has neither veil nor operculum* * * § . The 
Purpura, Brufj. 
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. I'he Purpurae were 
scattered among the Buccina and the Murices of Linnaeus. The ani- 
mal resembles that of a true Buccinumf. 
The genus Licorne, Month, — Moxoceros, Lam., consists of shells 
similar to the Purpurae, but in Avhich the external edge of the emar- 
gination is furnished with a salient spine;J;. 
Others, also resembling the Purpui’cc, in which the columella or 
at least the margin is provided, in the adult, with teeth which narrow 
the aperture, form the Sistra, Month, or the Ricinula, Lam.§ 
CoNCHOLEPAs, Lain . 
The general characters of the Purpurje, but the aperture is so 
enormous, and the sihrc so small, that the shell has almost the appear- 
ance of a Capulus, 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 tlie exception of its foot, which 
is enormous in Avidth and thickness, and that it is attached to the shell 
by a muscle shaped like a horse-shoe, as in the Capuli ; it has a thin, 
narroAV, and horny operevdum. 
But a single species is knoAvn, the Buccinum concholepas, 
Brug. ; Argenv., pi. ii, f. F, D; and SoAA^erb., Gen. of Shells, 
No. VI. From the coast of Peru. 
Casis, Bruej. 
The shell oval ; aperture oblong or narroAv ; the columella covered 
Avith a plate as in Nassa, and that plate transversely plicated, as Avell 
as the external margin ; the emargination terminating in a short 
canal, that is reflected and piished back, as it Avere, to the left : 
A’-arices are frequently observed on it. The animal resembles that of 
a true Buccinum, but its horny operculum is denticulated, in order 
to pass betAveen the plicae of the external margin. 
* Buccinum harpa, L., and the other species long confounded Avith it — List., 992, 
993, 994; Mart., Ill, c.xix: Bucc. cosfatum, Ib. Messrs. Reynaud, Q.uoy and 
Gaymard have observed, that, under certain circumstances, the posterior part of the 
foot is spontaneously detached. 
•t Buccinum persicum, List., 987, 46, 47 ; — B. putulum, Id., 989, 49 ; — B. hcB- 
masloma, Id., 988, 48 ; — B. trochlea, B. lapiUus, Id., 965, 18, 19 ; — Murex fucus, 
Id. 990, 50 ; — Mur. histrix, Martini, III, ci, 974, 975 ; — Mur. mancinella., List,, 
956, 8, 957, 9 — 10; — Mur.hippocastanum, List., 955, 996, 990, 991. 
Buccinum monodon, Gm., Martini, III, Ixix, 761 ; — Bucc. narcal, Brug. \—B. 
unicorne, Id. 
§ Murex ricinis, L., Seb,, III, lx, 37, 39, 42; — Mur. ncrilotdeus, Gm., No. 43, 
List., SOI, 12—13. 
