CONCHIFERA. 437 
| Faminy VII.—CHAmMIpD&@. 
Sheil inequivalve, thick, attached ; beaks sub-spiral ; ligament 
external; hinge-teeth 2 in one valve, 1 in the other; adductor 
impressions large, reticulated ; pallial line simple. 
Animal with the mantle closed; pedal and siphonal orifices 
small, sub-equal; foot very small; gills two on each side, very 
unequal, united posteriorly. 
CHAMA (Pliny), L. 
Example, C. macrophylla, Pl. XVIII., Figs. 8, 9, 
Synonym, Arcinella, Schum. 
Shell attached usually by the left umbo; valves foliaceous, the 
upper smallest ; hinge-tooth of free valve thick, curved, received 
between two teeth, in the other; adductor impressions large, 
oblong, the anterior encroaching on the hinge-tooth. 
Animal with the mantle-margins united by a curtain, with 
two rows of tentacular filaments; siphonal orifices wide apart, 
branchial slightly prominent, fringed, anal with a simple valve; 
foot bent, or heeled; liver occupying the umbo of the attached 
valye only ; ovary extending into both mantle-lobes, as far as 
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Fig. 224. Left side. 
Fig, 223. Right side. 
fig. 223. Right side, with the umbonai portion of the mantle removed. 
Fig. 224, Left side, showing the relative extent of the liver and ovarium 
a, a, adductors; m, pallial lino; e, excurrent orifice; b, branchial; f, foot and 
pedal orifice; p, posterior pedal muscle; ¢, palpi; g, gills (contracted) ; 7, liver; 0; 
ovarium ; d, dental lobes. 
the pallial line ; lips simple, palpi small and curled ; gills deeply 
plaited, the outer pair much shorter and very narrow, furnished 
with a free dorsal border, and united behind to each other, and 
to the mantle ; adductors each composed of two elements. 
