BIVALVIA. 273 
2. NEH®RA CUSPIDATA, Olivi. Tab. XXX, fig. 6. 
TELLINA cusPIDATA. Oliv. Zool. Adriat., p. 101, pl. 4, fig. 3, a—c, 1792. 
os — Broce. Conch. Foss. Subap., p. 515. 
ANATINA BREVIROSTRIS. Brown. Ed. Journ. Nat. and Geo. Sci., vol. i, p. 11, pl. 1, 
figs. 1—4, 1829. 
THRACIA BREVIROSTRA. Brown. Ill. Conch. Gr. Br., pl. 44, figs. 11—14, 1845. 
Nemra BREVIROSTRIS. Lovén. Ind. Moll. Scand., p. 48, 1846. 
— cusprmpata. Ford. and Hanl. Hist. of Brit. Moll., p. 195, pl. 7, figs. 4—6; and 
pl. & (animal), figs. 4—7, 1848. 
— _ Forbes. Aigean Inv., p. 185. 
Corsuta cuseipaTa. Phil. En. Moll. Sic., vol. i, p. 17, t. 1, fig. 19; and vol. ii, p. 12. 
—  suBrosTRATA. S. Wood. Catalogue, 1840. 
A fragment only of a shell, which I consider to belong to this species, was found 
by myself in the Coralline Crag at Sutton, but it is insufficient for correct descrip- 
tion: the peculiar form of the siphonal side (the portion I possess) is so characteristic 
that it is introduced here without much hesitation. It appears to have belonged to 
the British or short beaked variety. 
CorBuLA.* Bruguiére, 1792. 
Mya (sp.) Linn. Mont. Lentipium, Cristof. and Jans. 1832. 
Carpium (sp.) Walker and Boys. Poromomya, J. Sowerby, 1835. 
TELLINA (sp.) Olivi. Azara, D’Orb. 1839. 
ALoIpES, Megerle, 1811. | Corgutomya, Nyst, 1843. 
Generic Character. Shell suborbicular or ovate, inequivalve, inequilateral, tumid, 
closed; beaks prominent, recurved surface smooth or striated; in the recent state 
covered with an epidermis. Hinge composed of one thick, conical tooth in each valve. 
Ligament internal. Impression by the mantle with a small sinus. 
Animal short; mantle open in front for the emission of a thick foot, of 
considerable magnitude; siphonal tubes short and united to their orifices, which 
are fimbriated : anal opening with a conspicuous tubular membrane. 
Animals constituting this genus are for the most part inhabitants of salt water, but 
some are estuary species, and extend their range in the river to where the water is 
quite fresh. A separation has been proposed, under the name Potomomya, for those 
species which permanently inhabit fresh water, but the characters of shell and animal 
differ in no other respect from those which are truly marine. In this genus, as well as 
in that of Pandora, the two valves are very unequal in size, but this inequality is not 
confined to the siphonal side of the shell, and the sinus of the mantle-mark does not 
*Etym.? Corbula, a little basket. 
36 
