CHEMNITZIA. 433 



cylindrical and narrow, and on the march, as is the invariable 

 practice in all the species, it is in advance of the anterior 

 portion of the foot, which, like the terminus of the rostrum, is 

 truncate and without the auricular points at the angles ; it is 

 rather broad, and when extended reaches halfway on the 

 antepenultimate volution, posteriorly becoming a little con- 

 stricted, and having a very rounded termination. The tenta- 

 cula are triangular, bevelled laterally, pointed, with the usual 

 two minute flake-white lobes at the tips, which may be partly 

 real, but principally simulations that depend on the will of the 

 animal ; the lateral membranes, which are not so extensive as 

 in some species, coalesce and form a shallow veil ; the eyes 

 are very close together exactly at the internal bases, not im- 

 mersed, but a little elevated on minute prominences. We 

 may remark, that in this tribe the membranes on both sides 

 of each tentaculum simulate all kinds of shapes and foldings, 

 which have been termed auriform or subtubular ; these are 

 deceptions, and due to the will of the animal, as on the march 

 the tentacula are always carried in a regular, smooth, trian- 

 gular, bevelled position. These changes from one form to 

 another only occur when the animal is disquieted ; they are 

 then frequently and suddenly made, and the tentacles as 

 quickly assume a natural form. The operculum is of a narrow, 

 rather elongated, oval shape, carried on a simple lobe at some 

 little distance from the posterior terminus of the foot; it 

 has the usual, characteristic, right-angled, semi-cartilaginous, 

 minute, notched apophysis and oblique striae of the tribe. 



The animal is not at all shy, progresses rapidly, and in- 

 habits the coralline zone at Budleigh Salterton, where we 

 have taken it in 12 fathoms water, more than once, alive. 

 The animal has not before been described. 



CH. ELEGANTISSIMA, Mont. 



Ch. elegantissima, Brit. Moll. iii. p. 242, pi. 93. f. 1, 2; and iv. p. 275. 

 Animal inhabiting a white, spiral, elongated, glabrous shell 

 of 12-16 costated volutions ; it is, except the eyes, hyaline- 

 white throughout. The produced rostrum is deeply grooved 

 in the middle on the upper surface, and imperforate at the 



2 P 



