220 CLASS III. GASTEROPODA. ORDER VII. PECTINIBRANCHIATA. 
They became objects of especial notice in that age on account of the very 
limited sources then known of obtaining the purple colour, and were 
esteemed as objects of utility rather than of physiological interest. The 
property of exuding this liquor is not at all subservient as a character 
to the purposes of classification ; it is common alike to the Murices, 
Ianthine, Scalarie, and many others of the most anomalous organization. 
The term Purpura was, perhaps, applied more especially to the Murices ; 
it seems, however, to have been abandoned, until Lamarck selected it for 
the sake of distinguishing those mollusks which come under our present 
consideration ; a group whose shells are well characterized by the flatness 
of the columella. ‘They are excessively numerous in species, notwith- 
standing the separate arrangement of the Ricinule, Monoceri, and Concho- 
lepas. Lamarck originally included these three genera with the Purpure, 
and we only regret that both Duclos and Kiener should have returned to 
the early plan of arrangement. 
The shell of Purpura may be described as being of an oval or oblong- 
oval form, with the outside generally armed with spines or tubercles, the 
spire being short, and the last whorl ventricose, or widely inflated ; the 
aperture is ovate, and dilated, angulated at the upper part, and slightly 
canaliculated with an oblique sinus at the lower; the columella is flat, 
and depressed, ending in a point, and the lip is often dentated. The 
operculum is horny, and fits closely to the aperture. 
Examples. 
Pl. CCLIX. . Fig. 1. 
Purpura patuLa, Lamarck, Anim. sans vert., vol. vii. p. 236. Kiener, 
Iconographie des Coquilles vivantes, pl. 24. 
Perdicea nodosa, Petiver. 
Cymbium tuberosum patulum, Martini. 
Buccinum patulum, Linnzus. 
Pl. CCLIX. Fig. 2. 
Purpura succincta, Lamarck, Anim. sans vert., vol. vil. p.236. Kiener, 
Iconographie des Coquilles vivantes, pl. 27. f. 23. 
