228 ASTARTIDiE. 



GooDALLioPSis, Raincourt and Munier, 1863. 



Distr. — G. Orhignyi^ Rainc. and Mun. (cxxi, 19, 20). Eocene ; 

 Ferconrt. 



Shell oval, flattened, eqnivalve, 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. 



Diatr. — Oligocene ; Germany. Cretaceous ; So. India. G. 

 semicostata^ Speyer (cxxi, 21, 22). 



Shell roundish, moderately eompi'essed, 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 impressions oval, 

 moderatel}^ 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 (Crassatellidse), in which the pallial line is truncate pos- 

 teriorly, or more or less distinctly sinuated. 



Pr^conia, Stoliczka, 1810. 



Syn. — Hippopodium, d'Orb. (in part). 



Distr. — Oolite — . P. terminaUs^ Romer. 



Shell oval, elongated, solid, very inequilateral, beaks sub- 

 anterior, approached, incurved, surface concentricallj^lamellated 

 or striated ; muscular impressions strong ; hinge with two car- 

 dinal teeth in the left and three in the I'ight 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 

 anj^ known from cretaceous deposits. 



Alveinus, Conrad, 1865. 

 Distr. — Tertiary; Miss. A.minuta, Conr. (cxxi, 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. 



