170 Couthouy's Monograph on 
characters of the genus, so far as can at Hr be de- 
termined, are as follows : 
Genus Cocutoprsma, Couthouy. 
Animal oval, compressed, enveloped in a thin mantle, 
closed by a membrane in front, except at the anterior 
inferior extremity, where it opens to give passage to a 
broad, compressed foot, extending along the whole infe- 
rior surface of the. abdominal mass, which is inconsid- 
erable ; edges of the pallium thickened and a little ru- 
gose ; siphons, long, slender, divided in their whole 
extent, and sind separately into the branchial cavity. 
Branchiz ? Cue 
Shell transversely oval, thin and fragile, subequilat-- 
eral, convexo-depressed, slightly gaping at both ex- 
tremities, inequivalve, right valve the more Eres 
beaks moderately prominent, inclining; a lit back- 
wards, summits cloven and sub-nacrous | posteri y; ; ex- 
tremities rounded. Ligament double, the external very 
slight and membranous, the internal received into a 
horizontal, spoon-shaped process on each valve, sup- 
ported by one or two divergent, falciform coste, pro- . 
jecting from it obliquely and posteriorly ; ; muscular im- 
r 
ee 
pressions superficial, remote, the anterior elongated-oval, . Mi a " 
` the posterior gmáll- and subito gulir, united by a nit 
-leal impression profoundly indented posteriorly. 
| Cocnitopzswá PO E 
Synonyms. ifeann Leána, Mts Journ. Acad. 
Nat. Sci. V1. 263. 
Cochlodésma Leana, Noms 
