CONCHIFERA. 741 
Cardium isocardia L., Rumpu. Amb. Rariteitk. Tab. 48, fig. 9, CHEMN. 
Conchyl. Tab. 17, figs. 174—176, &e. 
Hemicardium Kurry, Spencier, Cuv. Valves compressed, a keel 
dividing the anterior from the posterior plane. 
Sp. Cardium hemicardium L., Rumen. Amb. Rariteitk. Tab. 44, fig. H, 
Buarnv. Malac. Pl. 70 bis, fig. 4 ;—Cardium cardissa L., Lam., Rumpu. 
1. 1, Tab. 42, fig. E, &c. 
Of the genus Cardiuwm SprNGLER has given a monograph, Skrivter af 
naturhist. Selskabet, V. 1. 1799, pp. I—60, Tab. I. 
The fossil species of Cardiwm are uncommonly numerous, they occur 
especially in tertiary formations. 
Isocardia LiAM. Shell cordate, with points involute spirally. 
Two cardinal teeth under the points, compressed, entering ; a single 
lateral tooth posterior, elongate. Animal (Glossus Pout) with foot 
compressed and tentacles of mouth elongate, acuminate. 
Sp. Jsocardia cor, Chama Cor L., Buatnv. Malac. Pl. 69, fig. 2, Pout 
Testac. utr. Sic. U. Tab, Xxul. figs. 1, 2 (I. Tab. Xv. figs. 34—36 animal) ; 
Mediterranean, &c.; also fossil. Much more numerous are the extinct 
species of this form, which for the most part occur in secondary formations. 
Opis DEFRANCE. Fossil genus. Is this its place ? 
Comp. DrsHayEs in LAMARcK Hist. n. d. Ani. 8, v. VI. pp. 519, 520. 
Cypricardia LAM. Shell inequilateral, elongate posteriorly, 
oblique or transverse. ‘Three teeth under the points; lateral tooth 
single, posterior, compressed, acute. 
Sp. Cypricardia oblonga Dusu., Chama oblonga L., Cypric. guinaica Lam., 
Buainy. Malac. Pl. 65 bis, fig. 6, DesHayEs Conchyliol. Pl. 24, figs. 8, 9, 
&e.;—Here belong also petrified species from the oolite and chalk 
formations. 
Family XIII. Veneracea. Mantle with lobes fimbriated at 
the margin, concrete posteriorly, open anteriorly for the passage of 
large, compressed, acute foot ; two trachez moderate, often coalesced 
at the base. Ligament external, short. Shell equivalve, free, 
regular, shut. Mostly three cardinal teeth, diverging obliquely 
from the point; lateral tooth in some single, posterior, in most 
none. 
Astarte SowErBY, Crassina LAM. Cardinal teeth two, diver- 
gent. Impression of mantle simple. Shell transversely rugose or 
