912 LUCINIDA. 
kind of a roundish or spoon-shaped process below the beaks ; 
muscular impressions rounded. 
SuspraMity CORBIN. 
Shell generally elongately ovate, or ovately rounded, solid, 
with muscular impressions subequal, broadly ovate, the ligament 
always external. 
Corsis, Cuvier, 1817. 
EHtym.— Corbis, a basket. 
Syn.—Fimbria, Muhl., 1811, not Bohadsch. Idotea, Schum., 
1817. Gafrarium, Bolten, 1798. 
Distr.—b5 sp. India, China, } North Australia, Pacific. Fossil, 
80 sp. (including subgenera). Lias— ; United States, Europe. 
C. fimbriata, Linn. (exix, 51). 
Shell oval, ventricose, subequilateral, concentrically sculptured ; 
margins denticulated within; hinge-teeth two, laterals two, in 
each valve; pallial line simple; umbonal area with an oblique 
furrow, muscular impressions round and polished; pedal scars 
close to adductors. 
Animal with the mantle open below, doubly fringed ; foot long, 
pointed ; siphonal opening single, with a long retractile tubular 
valve; lips narrow; palpi rudimentary; gills single on each 
side, thick, quadrangular, plaited, united behind. 
In C. dubia (Semicorbis), Desh., from the Eocene, Paris, the 
lateral teeth are obsolete. 
SPH@RA, Sow., 1822. (Paleocorbis, Conrad, 1869.) Shell 
ovate, inflated, solid, subequilateral; hinge of left valve with two 
blunt cardinal teeth, the posterior much smaller and separated 
from the larger anterior by a pit; lunular edge somewhat extended 
with a deep pit and a swollen tooth-like margin above and below 
it; posteriorly with a furrow near the fulcral margin and several 
cross-teeth at the posterior end; ligament in a long excavated 
furrow. Type, C. corrugata, Sowb. (cxix, 52. Neocomian 
MUTIELLA, Stolicz., 1870. Shell oblong, subequilateral, tumid, 
with obtuse incurved beaks; hinge in the left valve with two 
cardinal teeth, the anterior one being sometimes bifid, in the 
right valve there i is a single large bifid cardinal tooth; lunular 
edge expanded, with several teeth, or with more or less distinct 
corrugations , representing anterior ‘lateral tooth; posterior hinge 
side straight with a furrow near the margin for the ligament, and 
an indistinct terminal posterior lateral tooth. C. coarctata, 
Zitt. (cxix, 56,57). This group differs essentially by the char- 
acters of the hinge from the previous; there are several middle 
and upper cretaceous species which belong to it, but none are 
known from more recent deposits. 
SPHERIOLA, Stoliczka, 1870. Shell rounded, globose, nearly 
equilateral, with concentric striz or sulci on the surface; hinge 
