FAMILY 10. PURPURIFERA. 223 
= 
in the shells under consideration is developed in a very remarkable de- 
gree, we should have hesitated to receive it as a generic character, for a 
tooth of somewhat analogous construction may be indistinctly traced in 
the shells of some of the Turbinelli, Murices, and other canaliferous mol- 
lusks. But in none of these instances does it assume the importance and 
particular character which it exhibits in the shells of the Monoceri, and 
we therefore feel less hesitation in adopting a genus, which Kiener and 
others have very recently abandoned. The Monoceri are referred by 
these authors to the genus Purpura, as a section, under the title of 
“* Les Pourpres Licornes ;” but in this arrangement they are compelled to 
remove the Monoceros cingulatum to the genus Turbinellus, on account of 
the columella in that species being slightly plaited. 
The shell of Monoceros may be described as being ovate, with the spire 
sometimes a little elevated, sometimes a little depressed ; the last whorl, 
which is generally much inflated, is emarginated at the base, and somewhat 
inclined into a very short canal ; the columella is wide, and flattish as in the 
Purpure, and it is sometimes though very rarely plaited, the plaits being 
very small ; the aperture is nearly semilunar ; and the lip, which is gene- 
rally crenated, is always armed at the lower part with a very sharp, long, 
recurved tooth. The operculum is horny. 
Examples. 
Pl. CCLXI. Fig. 1. 
Monoceros rmpricatum, Lamarck, Anim. sans vert., vol. vil. p. 251. 
Encyclopédie Méthodique, pl. 396. f. 3. a,b. Chemnitz, Conch., 
vol. x. pl. 154. f. 1469 and 1470. 
Buccinum calcar, Martyn. 
Buccinum monoceros, Chemnitz. Bruguiére. 
Buecinum monodon, Gmelin. 
Purpura imbricata, Kiener. 
Pl. CCLXL. Fig. 2. 
Monoceros Breve, Sowerby, Genera of Shells, No. 5. 
Monoceros imbricatum, var. ? 
