CONCHIFERA. 
which gives that valve the appearance of having an indistinct 
or obscure cardinal tooth. 
Distribution, 4 species. Europe. 
Fossil, Tertiary. ‘Two of the three British species occur in a 
fossil state in the Coralline Crag. 
SPORTELLA, Deshayes (see p. 457). 
Heample, Psammotea dubia, Defrance. 
Shell oblong, smooth, depressed, sub-equilateral; valves 
closed. Hinge narrow, with two unequal, diverging teeth in 
the left valve, one in the other; the lateral teeth are wanting. 
Muscular scars large, oval, nearly equal; pallial line simple. 
Ligament external. 
Fossit, 17 species. Tertiary. Paris basin. 
Possibly some of the Liassic species referred to Unicardium 
belong to this genus. 
CorBICELLA, Morris and Lycett, 1853. 
Etymology, diminutive of Corbis. 
Type, C. subsequilatera, Lycett. 
Shell destitute of ornament, ovately elongated, rather com- 
pressed ; anterior side small; hinge characters differ from those 
of Corbis, in the absence of the anterior lateral tooth, and in 
the oblique internal ridge passing downwards behind the ante- 
rior muscular scar. 
Corbicella is intermediate between Corbis and Tancredia; and 
from the latter, to which it is more nearly allied, it is separated 
by its more ovate form, and by the absence of the posterior 
oblique angle, and in the possession of a lengthened hinge- 
lamina and depressed remote posterior lateral tooth. 
Fossil, 7 species. Upper part of Inferior Oolite—Oxfordian. 
England; France. 
[Faminy KELLIIDZz. | 
LAsz#A, Brown, 1827. 
Etymology, possibly a corrupt derivation of Aaozjiov, a shield. 
Type, Cardium rubrum, Montagu. 
Synonyms, Poronia, Recluz; Cyleadina, pars; Kellia, pars; 
Bornia, pars. 
Animal with the mantle folded on the anterior side so as te 
form a wide but incomplete incurrent tube; the excurrent tube 
is inconspicuous, placed on the opposite side; foot long. 
EB 73 
