PANDORA. 151 
tumid than the right: the mantle is closed, except a small 
fissure at the anterior end for the issue of the foot ; posteriorly 
it forms a sheath, which encloses the very short, scarcely 
separated siphons, that merely show their extremities, which 
are fringed at the orifices with fine white short cirrhi; the 
margin of the sheath, in some specimens, is marked with a fine 
orange line, and the base of the cirrhi and margins of the ori- 
fices are usually encircled with a dead-white narrow thread. 
_ With regard to the branchiv, I have great satisfaction in 
stating, that after the examination of many live specimens, I 
am enabled to settle the true character of them. I have been 
most anxious on this head, as the statement in the ‘ British 
Mollusca,’ pp. 210-212, is given from old notes of mine in 
1835, in which it is observed, that there are two palpi and 
one branchial lamina. Later and repeated examinations 
require the following rectifications. I can now say, beyond 
dispute, and show the fact by preparations, that there are two 
palpi and two branchie on each side of the body ; the branchize 
run horizontally, beg long, narrow, slightly arcuated, and 
symmetrical, pale brown, and pectinated by the blood-vessels 
on both surfaces ; their posterior pomts pass into the branchial 
tube ; the palpi are short, small, pale brown, triangular, pomted, 
and striated transversely. The ovarium is orange-coloured, and 
placed posterior to, and in contact with, the dark green liver : 
in the genial months the ova, in all stages of development, are 
very conspicuous, which, we think, on exclusion pass, without 
any delay in the branchiz, mto their native element. The 
intestine passes out of the posterior basal part of the liver to 
the bottom of the body, and then ascends under the branchiz 
and adductor muscle to its termination in the anal tube. 
This very elegant species, both as to the animal and shell, 
is sufficiently plentiful, alive, at Exmouth, in the coralline 
zone. 
P. rostrata, Lamarck. 
P. rostrata, Brit. Moll. i. p. 207, pl. 8. f. 1-4. 
This species is an inhabitant of the Channel Islands; we 
believe there is no well-authenticated capture of a live animal 
on the strictly British coasts. 
