PILEOPSIS. 265 
hues of the rose. The Emarginule present similar conditions. 
This remark is of some value to confirm natural position. 
The mantle thickens gradually from the vertex to the base, 
and is coloured in different individuals white, or tinted with 
pale pink, and is also bordered with a dull red frmge. The 
head is an elongated, grooved, emarginate muzzle ; the tenta- 
cula are yellow, long, tumid at the base, conically tapering as 
in Patella, with eyes on distinct but not much raised emi- 
nences at the external bases. The branchial apparatus consists 
of a heart and one auricle, and a series of long pale brown 
filaments, which spring from the base of the walls of the 
cervical cavity, and do not present a compact plumose leaf. 
The foot is tough, coriaceous and circular, with an anterior 
puckered ruff, or upper skin, or sort of mentum. This leads 
me to observe again on the fact mentioned on my authority 
in the ‘ British Mollusca,’ that the matrix, or part thereof, is 
sometimes, perhaps always, detached, and deposited on the 
neck of the foot, for further development of the ova, for some 
time previous to being committed to take care of themselves. 
The same phenomenon is observable in Janthina, which will 
be fully spoken of hereafter ; and I will now add, that with 
respect to the so-called rudimentary lamina, which is stated, 
though I have never seen it, to be sometimes observed on the 
foot of this species, that it probably has its origin in a com- 
pressed mass of testaceous pulli in adherence with it. 
Our examples, being taken many years ago from oysters 
brought into Exmouth by the French dredgers for the oyster 
plantations at Lympstone, though fresh, were sluggish, and 
did not enable us to complete the descriptive notes with all 
the accuracy that was desirable. 
Calyptrea and this species are exceedingly rare on the 
southern coasts, off Exmouth, but, thirty years ago, the 
P. hungaricus were found in abundance in Torbay ; this is 
not so now: their disappearance is probably owing to the 
oysters being all dredged, or buried beyond extrication by 
the shifting of the marine beds of shmgle. Our supplies 
from the Jerseymen’s trawl vessels have long been cut off, 
in consequence of the French and English governments, to 
