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ASTARTIDA. 
GoopALLiopsis, Raincourt and Munier, 1863. 
Distr.—G. Orbignyi, Paid and Mun. (cxxi,19,20). Eocene; 
Fercourt. 
Shell oval, flattened, equivalve, inequilateral, smooth, slightly 
dilated in front, and compressed behind; valves closed ; hinge 
with two cardinal teeth, separated by a triangular socket, in 
each valve; lateral teeth distinct and elongated, one in each 
valve. Other characters those of Goodallia. 
GROTRIANA, Speyer, 1860. 
Distr.Oligocene; Germany. Cretaceous; So. India. G. 
semicostata, Speyer (cxxi, 21, 22). 
Shell roundish, moderately compressed} concentrically sul- 
cated or striated, lunula and area very deeply excavated; beaks 
produced and pointed, hinge with two or more (often three) car- 
dinal teeth in the right and two in the left valve, the middle 
tooth in the former and the anterior in the latter being the 
strongest ; each valve with a rib-like marginal lateral tooth on 
either side ,accompanied by a groove, muscular i impressions oval, 
moderately excavated, internal margin finely crenated. 
This genus greatly resembles in external form an Astarte, but 
is readily distinguished from it by the presence of the peculiarly 
elongated lateral teeth and the deep lunula and area. The car- 
dinal teeth equally easily distinguish the genus from Eriphyla, 
Gabb (Crassatellide), in which the pallial line is truncate pos- 
teriorly, or more or less distinctly sinuated. 
Praconta, Stoliczka, 1870. 
Syn.—Hippopodium, d’Orb. (in part). 
Distr.—Oolite—. P. terminalis, Romer. 
Shell oval, elongated, solid, very inequilateral, beaks sub- 
anterior, approached, incurved, surface concentrically lamellated 
or striated; muscular impressions strong; hinge with two car- 
dinal teeth in the left and three in the right valve, the anterior in 
the latter being often obsolete, and the posterior are in both 
elongated; sometimes there appears to be an indication of a 
posterior lateral tooth. This genus includes a great number of 
chiefly lower and middle mesozoic species; there are scarcely 
any known from cretaceous deposits. 
ALVEINUS, Conrad, 1865. 
Distr.—Tertiary ; Miss. A. minuta, Conr. (exxi, 23 
Shell smooth, anterior, posterior and ventral margins chan- 
neled within; hinge of right valve emarginated under the apex, 
and having one pyramidal tooth anteriorly ; hinge of the left 
valve with a pit under the apex, and two diverging teeth 
anteriorly. 
