108 CYPRINID A. 
dead specimen of that species has been taken; but we have 
often seen the minute dA. triangularis alive. Cyprina and 
Isocardia by their hmges indicate some alliance with the 
Cardiade. 
This family has considerable affinities with the Veneride, 
but is distinguished by the very short, almost sessile siphons, 
and the consequent absence of pallial impression so con- 
spicuous in that group. 
CYPRINA, Lamarck. 
C. Istanpica, Linneus. 
C. Islandica, Brit. Moll. 1. p. 441, pl. 29; (animal) pl. M. f. 4. 
Animal suborbicular, thick, bluish-white; mantle open, 
powdered for some depth, on a pale yellow ground, with 
minute red-brown sandy points; its edge is finely dentated 
and marked with a slender brown lne. The foot is thick at 
the base, moderately long, linguiform, and posteally lanceolate. 
The mantle forms no tubes, but mere sessile orifices, both of 
which are ciliated ; the branchial is the largest, having about 
twenty simple cirrhi, the anal about ten ; both are tmged with 
red-brown; the anal orifice at its terminus frequently pro- 
trudes a globular transparent membranous valve, which regu- 
lates the entry and issue of the water; the margins of both 
orifices at the base of the cirrhi have a girdle of a narrow 
bright red line, the hues of which vary in individuals even 
from the same locality. 
This species usually inhabits the littoral sandy districts, but 
at Exmouth is obtained in an offing of five or six miles. 
ISOCARDIA, Lamarck. 
I. cor, Linneus et Auct. 
I. cor, Brit. Moll. i. p. 472, pl. 34. f.2; (animal) pl. N. f. 6. 
“ Animal globular; mantle completely lining the shell, 
double at the outer edge; exterior fold divided in front, open 
