224 CRASSATELLIDA. 
( Carditacea.) 
Famity CRASSATELLIDA. 
Shell oblong, posteriorly usually somewhat produced, mostly 
concentrically 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 ; 
pallial line entire. 
CRASSATELLA, Lamarck, 1799. 
Etym.— Crassus, thick. 
Syn.—Pachythzrus and Scambula, Conrad. 
Distr.—34 sp. Australia, New Zealand, Philippines, India, 
West Africa, Canaries, Brazil. Fossil, 64 sp. Cret.—; Patagonia, 
United States, Europe. C. Antillarum, Reeve (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- 
form, slightly grooved; palpi short and broad, few-plaited ; 
outer gill narrower in front. 
CRASSITINA, Weinkauff, 1881. Proposed for the smaller species, 
with crenated margins of the valves. 
PrycHomya, Agassiz, 1842. 
Syn.—Radioconcha, Conrad, 1869. Pleuroconcha, Conrad, 
1872. 
Distr.—Oolitic, Cretaceous ; Europe, U. 8. TZ. 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 (exxi, 61, 62°. Cretaceous ; 
California. 
Shell narrow, compressed, posteriorly very elongated, ante- 
riorly shortly rounded, beaks obtusely pointed ; hinge with two 
elongated, somewhat diverging cardinal teeth in each valve; a 
