488 MURICID/. 
branchial fold, which in adult specimens is often exserted an 
inch beyond the emargination of the shell; it floats free, as 
there is no canal for its support; it is also evidently a tenta- 
cular aid. 
The colour of the upper part of the foot, of the tentacula as 
far as the eyes, and of the branchial fold, is a hght brown 
ground, so thickly studded with yellow flakes and minute dark 
points and blotches, as to give the animal a dark pepper-and- 
salt aspect; the under part of the foot is yellowish-brown, 
aspersed with very minute dark points. The head is small 
and flat, with two long tentacula, bearmg eyes externally on 
offsets about a quarter of an inch from the bases, where they 
are wide, but from thence to their termination they become 
slender and pointed. The foot is very large, long and broad, 
extending, when in full march, more than the length of the 
shell; it is bevelled to a fine edge, gently rounded, indented 
in the centre in front, and has slightly curved, rather long 
auricles ; it then gradually declines to an elongated lanceolate 
termination, which is emarginate, and sends forth from each 
fillet of the fork a pointed filament: close and anterior to the 
caudal emargination is a brown, corneous, suboval, subungui- 
culated operculum. I have thought that the emargination 
might be the seat of a gland, as that part is constantly covered 
with mucus, which, when removed, recurs ; but as I could trace 
no distinct duct, I presume the exudation is of porous origin. 
The mouth is a vertical fissure under the head, from which a 
very long proboscis is protruded, the structure of which is in 
all respects similar to that of Murex undatus, mihi (Buccinum 
undatum auctorum), as are the cerebral ganglia, the salivary 
glands, the double branchial plumes, the mucous fillets, and 
the heart and auricle; all these organs I have dissected and 
compared with the same parts of that species, without finding 
any essential differences. 
It appears from these notes, that the principal variations of 
this section of the Muricidal group from its fellow-species, 
consist in the large size and somewhat varied outline of the 
foot with its caudal filaments; but surely no malacologist 
will contend that these are generic distinctions: the whole of 
the animal must be taken into view, and this will undoubtedly, 
