236 CLASS III. GASTEROPODA. ORDER VII. PECTINIBRANCHIATA. 
The shell of Nassa may be described as being ovate, somewhat turrited, 
and terminating at the base with either a sinus, or very short, reflected 
canal ; the spire is somewhat raised, and sharp at the apex, and the whorls 
are generally more or less ornamented with longitudinal ribs ; the aper- 
ture is orbicular, and angulated at the upper part; and the columella, 
which is smooth, and sometimes very widely spread over with enamel, is 
furnished near its junction with the body whorl with either a callosity or 
blunt, dentiform plait ; the outer lip is dentated, and the interior is slightly 
crenulated. The operculum is horny. 
Examples. 
Pl. CCLXIX. Fig. 1. 
Nassa arcuxartia, Lamarck, Encyclopédie Méthodique, pl. 394. f. 1 and 2. 
Martini, Conch., pl. 41. f. 409 to 412. 
Arcularia major, Rumphius. 
Buccinum arcularia, Linneus. Kiener. 
Pl. CCLXIX. Fig. 2. 
Nassa Tuersites, Lamarck, Encyclopédie Méthodique, pl. 394. f. 8. a, b. 
Martini, Conch., pl. 41. f. 413. 
Arcularia minor, Rumphius. 
Buccinum Thersites, Bruguiére. Kiener. 
Pl. CCLXIX. Fig. 3. 
Nassa NERITEA, Lamarck, Encyclopédie Méthodique, pl. 394. f. 9.4, 6. 
Chemnitz*, Conch., vol. v. pl. 166. f. 1602. 
Buccinum neriteum, Bruguiére. 
Cyclops asterizans, De Montford. 
species of such divisions. Of the many genera included in his family of Buccinide, there are, 
however, several, such as Cythara, Quoyia, Demoulia, Ringicula, Litiopa, Lamprodoma, Aga- 
ronia, Scaphula, Olivella, &c., which we cannot judge of, as we have yet to learn the characters 
which entitle them to distinction. 
* Chemnitz appears to have confounded this shell with the Rotella. 
