FAMILY 12. CONVOLUTA. 269 
mollusks, it has never been thought susceptible of being dismembered. 
An attempt was certainly made by De Montford to establish three new 
genera from it, Rollus, Cylinder and Hermes, but in no case have they been 
followed, except in the plan laid out for the arrangement of our national 
collection. . 
The situation of this genus in the general system, like that of the pre- 
ceding, is still open to controversy. De Blainville places it immediately 
after Strombus on account of the resemblance in the formation of the 
shells of that genus in an early stage of growth; Deshayes includes it in 
his family of Buccinide ; and Gray, on the other hand, refers it to his 
family of Muricide after Pleurotoma. For our own part, we have followed 
Lamarck, rather against our inclination; for upon comparing certain 
species of Coni with the Pleurotoma mitreformis* we discover a resem- 
blance, which is increased by their being opereulated. 
The shell of Conus may be described as being conical, and emargi- 
nated at the base, with the whorls closely rolled upon their axis, and not 
descending ; the spire varies considerably, being sometimes acuminated, 
sometimes totally depressed ; it is, however, generally rather obtuse at 
the apex ; the aperture is longitudinal, and rather narrow ; the columella 
is straight, and the outer lip is thin, acute, and emarginated at the upper 
part. The operculum is horny and minute. 
Examples. 
Pl. CCXCII. Fig. 103. 
Conus centurio, Born. Mus., pl. 7. f.10.. Lamarck, Anim. sans vert., 
vol. vii. p. 466. Martini, Conch., vol. ii. pl. 59. f. 655. 
Vigiliarum prefectus, Martini. 
Conus tribunus, Gmelin. 
* However we may have had occasion to differ from Mr. Gray in regard to the generic 
distribution of the Mollusca, we admit the superiority of his views in this instance, and can 
only regret having omitted to follow a good example. It seems pretty well agreed amongst 
authors that the Cones are not strictly referable to the family of the Convoluta, though no 
two authors have yet agreed upon the exact situation they should be referred to. 
VOL. Il. 2N 
