224 CRASSATELLIDuE. 



( Carditacea.) 



Family CRASSA.TELLID^. 



Shell oblong, posteriorly usually somewhat produced, mostly 

 concentricall}?^ striated or sulcated, covered with an epidermis ; 

 hinge with a few cardinal teeth, and a cartilage-pit in both 

 valves ; lateral teeth, when present, slightly developed, elongated ; 

 palljal line entire. 



Crassatella, Lamarck, 1*199. 



Etym. — Crassus, thick. 



Syn. — Pachythserus and Scambula, Conrad. 



Distr. — 34 sp. Australia, New Zealand, Philippines, India, 

 West Africa, Canaries, Brazil. Fossil, 64 sp, Cret. — ; Patagonia, 

 United States, Europe. G. Antillarum, Beeve (cxxiii, 64). 



Shell solid, ventricose, attenuated behind, smooth or concen- 

 trically furrowed ; lunule distinct ; ligament internal ; margin 

 smooth or denticulated ; pallial line simple ; hinge-teeth 1*2, 

 striated, in front of cartilage-pit; lateral teeth 0—1, 1—0; 

 adductor impressions deep, rounded ; pedal small, distinct. 



Animal with mantle-lobes united only by the branchial septum ; 

 inhalent margins cirrated ; foot moderate, compressed, triangular, 

 grooved ; gills smooth, unequal, outer semilunar, inner widest 

 in front ; palpi triangular. 



In Crassatella pulchra the animal is like Astarte ; foot lingui- 

 forra, slightly grooved; palpi short and broad, few-plaited; 

 outer gill narrower in front. 



crassitina, Weinkauft', 1881. Proposed for the smaller species, 

 with crenated margins of the valves, 



Ptychomya, Agassiz, 1842. 



Syn. — Radioconcha, Conrad, 1869. Pleuroconcha, Conrad, 

 1872. 



Distr. — Oolitic, Cretaceous ; Europe, U, S, T. plana, Agass. 



Shell ovately elongated, moderately compressed, beaks close 

 together, placed subanteriorly, surface radiately ribbed, 

 anteriorly generally divaricately striated ; hinge with three 

 diverging cardinal teeth in each valve, and the cartilage-pit 

 situated in front of them ; muscular impressions elongately 

 oval, rather large ; pallial line truncate posteriorly. 



Anthonia, Gabb, 1864, 



Distr. — A. cultriformis, Gabb (cxxi, 61, 62). Cretaceous ; 

 California. 



Shell narrow, compressed, posteriorly very elongated, ante- 

 riorly shortly rounded, beaks obtusely pointed ; hinge with two 

 elongated, somewhat diA^erging cardinal teeth in each valve ; a 



