424 PYRAMIDELLID^E. 



index fails when the species is sometimes with and sometimes 

 without the denticle. 



This is a rare animal on the Devon coasts, but we have 

 taken several at Exmouth in the coralline zone ; it is by no 

 means shy, marching with vivacity, and allowing a good exa- 

 mination. 



Addendum. The tentacular veil, or, in other words, the 

 bases of the short, broad, leaf-bike tentacula, are not entire, 

 as stated above, but slightly emarginate in the centre, just 

 dividing the leaves, and with a groove in continuation of the 

 central indentation of the rostrum. 



The animal of this species is the southern variety mentioned 

 by the learned authors of the ' British Mollusca/ vol. iii. 

 p. 245, which is certainly the true C. rufa of Philippi and 

 authors. Professor Forbes and Mr. Hanley, in their account 

 of the " rufa," have stated, that it is with some hesitation 

 they have followed the suggestions of their friends : and well 

 they might pause, as they have described an entirely distinct 

 species, a northern one, the Chemnitzia fulvocincta of Thomp- 

 son and Alder, for the true rufa, which we found thirty years 

 ago at Exmouth, and of which we took five in 1850. The 

 description of the animal in the ' British Mollusca ' refers to 

 the C. fulvocincta, and appears to differ from ours of the true 

 " rufa " in those slight specialties which might be expected 

 in such congeneric creatures : it is really extraordinary how 

 two species so totally different, as to the hard parts, should 

 have been confounded. I will now state the distinguishing 

 characters of each. 



The C. fulvocincta is well figured in the ' British Mollusca/ 

 under the title of C. rufa ; it is more conical and tapers more 

 rapidly than the true C. rufa ; it has rarely more than eleven 

 or twelve volutions, and sixteen to eighteen ribs, somewhat 

 raised and sinuated ; each volution slopes from its base to the 

 ascending suture, which is merely a fine line ; it is very glossy, 

 with a most conspicuous yellow or orange band spirally 

 coasting the last five or six turns; the basal portion of the 

 aperture is subrotund. 



The genuine C. rufa is generally larger, though it has some 



