ACEPHALA TESTACEA. 413 



with long tubes which are received into a sinus of the mantle. 

 Some of them are found on the coast of France(l). The 



Cyclas, Brug. 



Separated from Venus by Brugiere, like the Cardia and Donaces, 

 has two teeth in the middle of the hinge, and before and behind, two 

 salient, and sometimes crenulated plates; but the shell, as in several 

 species of Venus, is more or less rounded, equilateral, and trans- 

 versely striated. The animal has moderate tubes. The external 

 tint is usually grey or greenish. The Cyclades inhabit fresh water. 

 One species, the Telllna cornea, L.j Chemn,, VI, xiii, 133, is 



very common on the coast of France(2). M. Lamarck separates 



the 



Cyrena, Lam. 



Where the shell is thick, slightly triangular and oblique, covered 

 with an epidermis, and otherwise distinguished from the Cyclades 

 by having three cardinal teeth. The Cyrense also inhabit rivers, 

 but there are none in France(3). 



Cyprina, Lam. 



Also separated from the Cyclades by Lamarck; the shell is thick, 

 oval, with recurved summits, and three stout teeth; further back is 



(1) Donaxrugosa, Chemn., VI, xxv, 250 252; D. trunculus, lb., xxvi, 253, 

 254:; D. striata, Knorr., Delic, VI, xxviii, 8;D. denticulata, Chemn., I, c, 256, 

 257\D. faba, lb., 266; Z). spinosa, lb., 258. Fossil species are numerous in 

 the environs of Paris. See Lamarck, Ann. du Mus., VIII, 139, and Deshayes, 

 Coq- foss. des Env. de Paris, I, pi. xvii, xviii. 



The Donax irregularis, from the Environs of Dax, described by M. Bastorat in 

 the Mem. de la See. d'Hist. Nat. de Paris, t. II, pi. iv, f 19, A, B, is the type of a 

 new genus lately established Bullet, de la Soc. Lin. de Bourdeaux, II, by M. 

 Charles Desmoulins, under the name of Ghatelupia. It is distinguished from the 

 Donaces by the presence of several dentiform lamellae which accompany the car- 

 dinal teeth. 



Several species of Venus, and some Madras, are mixed with these true Donaces 

 by Gmelin. 



(2) Add TelUna rivalis, Miill., Drap., X, 4, 5;Cyclas fontinalis, Drap., lb., 

 8 12; Ci/cl. caliculata, lb., 13, IA:;Tellina lacustris, Gm., Chemn., XIII, 135; 

 Tell, umnica, lb., 134; Tell. Jluviatilis; Tell. Jiuminalis, Chemn., VI, xxx, 

 320. 



(3) Tell, fluminea, Chemn., lb., 322, 323; Femts coaxans. Id., xxxii, 336, or 

 Cyrena ceylanica. Lam., Encyc. Method., pen., pi. 302, f. 4; Venus borealis, Id., 

 VII, xxxix, 312, 314; Cyclas cardiniana, Bosc, Shells., Ill, xviii, 4. Fossil spe- 

 cies abound near Paris. See Deshayes, Coq. Foss., I, pi. 18, 19. 



