488 MUBICIDJE. 



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 light 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, bearing 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, 



