ERYCINIDA. QT 
lous, with a simple insinuation or a slight notch; ligamental fur- 
row subinternal; lunule not excavated; muscular impressions 
ovate, marginal. 
PsatuuRA, Deshayes, 1860. 
Etym.—wavpis, friable. 
Type, Zrycina fragilis, Lamk. (exx, 76, 78). Eocene; Paris 
Basin. 
Shell oval, inequilateral, thin, transparent, fragile ; hinge-teeth, 
in the right valve, two equal and deeply bifid; left valve, two 
unequal, entire; ligament external; anterior adductor scar nar- 
row, claviform; posterior subquadrangular ; pallial line simple, 
thus differing from Clementia, to which it is related by the hinge- 
characters. 
Scacouta, Philippi, 1844. 
Distr.—2 sp. Mediterranean. Fossil, 1 sp. Pliocene; Sicily. 
S. elliptica, Phil. (exix, 75). 
Shell minute, ovate, posterior side shortest; hinge-teeth 1 or 
2, laterals obsolete; ligament minute; cartilage internal, in an 
oblong pit. 
Animal with mantle widely open; siphonal orifice single ; foot 
compressed, linguiform ; palpi moderate, oblong. 
Famity ERYCINIDA. 
Shells very small, thin, fragile, usually transparent, and some- 
times gaping, rounded or transverse, laterally depressed ; hinge 
narrow, with one or two cardinal teeth, the laterals more or less 
elongated, compressed, sometimes wanting; muscular impres- 
sions small, not well-marked ; pallial line simple. 
Eryoina, Lam., 1804. 
Distr.—12 sp.. Fossil, 50 sp. Cret.—Eocene—; N. Anm., 
Paris Basin. i. Geoffroyt, Payr. (exx, 25-27). 
Shell equivalve, subinequilateral, usually transversely oval; 
one, or two unequal, diverging cardinal teeth, separated by a 
pit; lateral teeth oblong, compressed, short; ligament external 
and internal; muscular impressions rounded, pallial line simple. 
ERYCINELLA, Conrad, 1845. 
Distr.—E. ovalis, Conr. Miocene; Virginia (cxx, 62); and 
Crag; England (cxx, 79, 80). 
Shell subtrigonal, inequilateral, thick; two cardinal teeth , 
separated by a pit in each valve; lateral teeth rudimentary ; 
ligament internal; pallial line simple. 
SpPANropon, Reuss, 1867. 
Type, S. nitidus, Reuss (cxx, 83, 84). Miocene; Galicia. 
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