BIVALVIA. 13 



also resemble the impression of the adductor in some of the capuloid shells, more especially 

 those of the Genus Hipponyx, in which the animal constructs a shelly base resembling a 

 second valve, and the adductor in that Gastcropod has the twofold purpose of the Bivalve 

 muscle, adhering to the shelly base as well as to the interior of the conical shell, forming 

 and leaving a similar mark deeply impressed upon the inner surface of each piece, the muscle 

 extending itself behind the foot, and this otherwise large " belly-foot'' of the Hipponyx is 

 contracted to permit it to take hold of the shelly base. These impressions in Anomia 

 indicate the presence of powerful muscles, although the animals possess little more than 

 the rudiments of a foot. The genus is far removed from those animals which have only- 

 one piece of shell (the Univalve), but they are perhaps nearer than any other Bivalves, and 

 they are, I think, appropriately placed here at the head of the list. 



In the recent state, this genus has an extensive geographical range, species belonging 

 to it are found in America, India, Australia, the Mediterranean, and the North Seas. 

 It is not numerous in species, cither as recent or fossil. 



1. Anomia tknuistriata, Deshaycs. Tab. IX, fig. 1, a — <\ 



Anomia stbiata. J. Sow. (non striata, Broc, 1814). Min. Conch., t. 425, 1823. 

 — — Galeofti. .Mem. Cour. par l'Acad. Brux., t. xii, p. 151, No. 89, 90. 



— epiiippium. Defrance. Diet, des Sc. Nat., t. 2, 1823. 



— tenuistkiata. Desh. Coq. Foss. des Env. de Par., t. 1, p. 377, pi. 65, figs. 7 — 11. 



— — Sow. In Dixon Geol. of Sussex, p. 117, t. 4, fig. 8; and t. 14, 



fig. 17, 1850. 



— — ? Grateloup. Cat. des An. du Bas de la Gironde, p. 56, 1838. 



— L.EviGATA? Nyst. Coq. Foss. Belg., p. 311, pi. 26, figs. 4—6, 1843. 



— orbiculata? Id. - p. 312, pi. 25, fig. 6, a, b. 



— LINEATA. J. Sow. Min. Conch. Syst., index, 1835. 



— — Morris. Catal. Brit. Foss., p. 161, 1854. 



Anomya tenuistriata. D'Orb. Prod. Palteont., p. 395, No. 1148, 1850. 



— substriata? Id. - - p. 396, No. 1 150, 1850. 



— subl.evigata ? Id. - - p. 396, No. 1 149, 1850. 

 Ostrea anomialis. Lam. Hist, des An. sans Vert., t. vi, p. 220, 1822. 



Spec. Char. A. testa tenui, suborbiculari, irregulari, valde inaquivalvi, valvd superiore 

 convexd, tenuissime striata, vahd inferiore plana for amine magno ; umbone submarqinali. 



Shell thin, irregular, rounded, and finely striated externally ; upper valve much the 

 larger and convex ; lower valve small, flat, and thin, with a very large opening for the plug ; 

 umbo near the margin. 



Diameter, 2 inches. 



Locality. Alum Bay, Barton, Bramshaw, Brockenhurst, Brook, Bracklesham, Bognor, 

 Clarendon, Stubbington, "Whitecliffe Bay {Edwards), Clewett's Green, Newnham (Prestwic/i), 

 Highgate ( Wetherell) . 



Belg., Env. de Bruxelles, Sables d'Ucclc et de Foret {Nyst). 

 "France, Grignon, Montmirail, Senlis {Desh.), Blaye {Grateloup). 



