806 CLASS XIII. 
** Canal elongate; sinus of labrum not contiguous to canal. Labrum 
produced into digitate lacinic. Pterocera LAM. 
Sp. Strombus Chiragra L., Lister Conch. Pl. 870, fig: 24 ;—Strombus Scor- 
pius L., D’AreENy. Conch. Pl. 14, fig. B, Buatnv. Malac. Pl. 25, figs. 3, 
4, GuéRIN Iconogr., Moll. Pl. 21, fig. 2, &e. 
*** Canal short, emarginate or truncated. Sinus of labrum distinct 
From canal. Labrum in more adult shells ecpanded into a wing simple, 
entire. Strombus Lam. 
Sp. Strombus gigas L., Lister Conchyl. Tab. 863, fig. 18 ;—Strombus latissi- 
mus L., LIstER Tt. 862, fig. 18 (856, fig. 12 young) ;—Strombus lentigi- 
NOSUS fey Cuv. R. Ani., éd. ill., Moll. Pl. 61, fig. 2, &e. 
Cassis Lam., Cassidea Brua. (spec. of Buccinum L.). Shell 
ventricose or inflated, with spire short. Aperture longitudinal, 
terminating in a short canal. Columella transversely plicate or 
rugose. 
a) Canal incurved obliquely to the left and upwards or substraight. Cas- 
sidaria Lam. 
Sp. Cassis echinophora, Buccinum echinophorum L., Rumex. Amb. Rariteith. 
Tab. 27, fig. 1, Gusrin Lconogr., Moll. Pl. 16, fig. 6, &e.—The genus 
Oniscia SOWERBY is distinguished by a short canal and a lamina, covered 
with granular inequalities, extending from the columella over the last 
wreath: Cassidaria Oniscus Lam., Strombus Oniscus L., &c. ‘See REEVE 
Conch. Syst. 1. pp. 210—212, Pl. 253, 254. 
b) Canal ascending, excised deeply towards the extremity. Cassis Lam. 
Sp. Cassis cornuta Lam., Buccinum cornutum L., ListER Conchyl. Tab. 
1008 ;— Cassis tuberosa LAM., Buccinuwm tuberosum L., Encycl. méth., Vers. 
Pl. 406, fig. 1, Pl. 407, fig. 2, Buatnv. Malacol. Pl. 23, fig. 1 ;—Cassis 
glauca LaM., Buccinum glaucum L., Rumen. Amb. Rariteitk, Tab. 25, figs. 
A and 4, Ouv. R. Ani., éd. ill., Moll. Pl. 56, fig. 1, &e. 
Fossil species also of this genus are found. 
Purpura Brug. Shell oval, often tuberculate, with spire short, 
last wreath ample. Aperture terminating in a sinus oblique, sub- 
canaliculate. Columella smooth, acuminate towards the apex. 
Operculum thin, horny. 
Ductos (Ann. des Sc. nat. XXV. 1832, pp. 90—9Q5, XXVI. pp. 103—112), 
DesHayes (Lncycl. méth., Vers. 111. pp. 838—845) and BLAINVILLE (Nowe. 
Ann. du Mus. 1. pp. 189—263) have united under the name of Purpura, 
besides Monoceros and Ricinula of LAMARCK, also Concholepas Lam. ; they 
regard these genera merely as divisions of a great genus, to which more 
than 200 species now belong. 
Ricinula Lam. Aperture oblong, narrowed by unequal teeth at 
the columella and the internal surface of labrum. Shell often tu- 
berculato-spinose. 
