CORBULA. 149 
CORBULA, Bruguwiere. 
C. nucteus, Lamarck. 
C. nucleus, Brit. Moll. i. p. 181, pl. 9. f. 7-12; (animal) pl. G. f. 3. 
Animal subtriangular, thick, yellowish-white ; mantle closed, 
except anteriorly, presenting an orifice having its circumference 
finely dentated, that marks the point of passage of a moderately 
long, subeylindrical byssal foot; posteally it forms two short 
united siphons, each with 8-10 cirrhi; the upper, or anal, has 
a hyaline, tubular, retractile, valvular, globular membrane, 
which is in frequent action, and appears to regulate the pro- 
pulsion of the fecal matters, and the ingress and egress of the 
water for the various purposes of the animal ceconomy, which 
will be fully explaimed in the observations on the Pholadide. 
On each side of the body there is a pair of very unequal 
branchiz, which hang obliquely, the upper being narrow, the 
lower larger and more triangular ; their colour brown, smooth 
on their outsides, and finely striated with ; on each side there 
are two long,narrow, pointed, brown pendulous palpi, pectinated 
strongly on both surfaces. Besides the red points circling the 
cirrhi of the siphonal tubes, there is a dark lme encompassing 
both at a short distance from the cirrhal circle of points ; these 
are better seen in the dead animal. The liver is black-green. 
We have taken, in the deepest part of the British Channel, 
conglomerations of many thousands of this species of all 
growths, having shells of brown and white, and often roseate 
hues ; they adhere to each other by fine silky byssal filaments. 
The C. ovata is a doubtful British species, and Mr. Wal- 
pole, of Monkstown, Co. Dublin, having favoured us with a 
specimen of his C. rosea, we can only consider it the common 
roseate variety of C. nucleus. Since the above remark, Mr. 
Walpole has informed us, that he has submitted specimens to 
Professor Forbes, who has come to the same conclusion. 
As to the C. ovata and C. rosea of the ‘ British Mollusca,’ 
we supply the following references :— 
C. rosea, Brown. 
C. rosea ? Brit. Moll. i. p. 185, pl. 9. f. 13, 14. 
C. ovata, Forbes. 
C. ovata? Brit. Moll. i. p. 187, pl. 9. f. 15, 
