396 MOLLUSCA SUB-KINGDOM VI 
Opis, Defr. (Fig. 709). Trigonal, cordate, smooth, or concentrically striate ; beaks 

Fic. 708. 
Astarte (Goodallia) 
miliaris, Defr. Eocene ; 
Grignon, near Paris 
(after Deshayes). 

SSSA Fic. 707. 
Woodia profunda, Desh. 
Eocene; Aizy, near Laon. 

Fic. 706. 

Astarte (Crassinella) obliqua, Desh. A, Hinge, enlarged. B, 
Inferior Oolite ; Bayeux, Calvados. Shell. 
prominent, prosocoelous ; lunule very deep, bordered by a keel; Fic. 709. 
cardinal teeth long, narrow (2:1). Trias to Cretaceous. Be Rolaieee a, 
. . oa ( rb. pper ura 5; 
Opisoma, Stol. Jura. Seebachia, Neumayr. Cretaceous. Nathan 
Family 5. Crassatellitidae. Dall. 
Shell as in the Astartidae, but the valves always somewhat unequal, and usually 
more or less rostrate, the beaks compressed, erect, or opisthocoelous ; ligament internal, 

Fic. 710. 
Crassatellites plumbea, Chem. sp. Eocene (Caleaire Grossier); Damery, near Epernay. 2/3. 
more or less obsolete, resilium large, wholly internal, attached at each end to a chondro- 
phoric pit in the hinge plate behind the cardinal teeth ; lateral teeth and sockets usually 
alternated in the valves, the hinge plate heavy, flat ; the posterior cardinal in the right 
valve very small or obsolete, with no distinct socket in the opposite valve; full cardinal 
L 1010 
ormula a7 Lower Cretaceous to Recent. 
f Ri0101 y taceous to Recent 
The earlier forms of this family have a small resilium close to the nearly marginal liga- 
ment. With time, later ones show a gradual descent of these organs, until in some of the 
