Tornatellidae, and Pyramidellidse. 445 



animal respires free air, or eliminates it from water, by a pectini- 

 branchous organ. 



I can say little of the Tornatellid(B with a single genus and 

 species, except that many years ago I examined the animal of 

 Tornatella fasciata, the type : I am inchned to think that, as re- 

 gards the characteristics of this tribe, it will here be nearly in a 

 natural position ; but as the animal is not unattainable, I propose 

 at a future opportunity to give both an anatomical and general 

 description of it. 



I observe, for the consideration of the younger naturalist, that 

 it matters not if one animal is terrestrial and pulmoniferous, and 

 another of marine or freshwater habitat and pectinibranchous — 

 they will take their natural position with respect to each other, 

 and in the method, as the collective value of the characteristic 

 organs either of one or the other preponderate ; for instance, the 

 Cyclostoma elegans, a land branchifer, falls into natural position 

 with the marine pectinibranchiata. And though Ca7'ychium and 

 Acme are pulmonifera, and the Pyramidellida branchifera, still the 

 peculiarity of their organs and shells associates them nearly as 

 closely with the marine as with the terrestrial mollusca. 



CONOVULID^. 



Conovulus bidentatus, Lamarck et auctorum. 



J, Conovulus albus et erosus, auct. 



Auricula bidentata, nonnuU. 



Animal spiral, with a white, glossy, short, fusiform shell of four 

 volutions, and an elongated nan'ow aperture. The colour through- 

 out the external organs is hyaline flake-white, except that occa- 

 sionally the termination of the muzzle and lobes of the head-veil 

 are margined with a fine red-brown line. The mantle is fleshy, 

 and sometimes extends rather beyond the aperture of the shell ; 

 when it is viewed in the dead animal, it has the aspect of the 

 rounded tumid margin of the Helices. The neck is propor- 

 tionately longer than any other animal of its size I am acquainted 

 with, and at its termination forms a veil divided by a sinuation 

 in its centre into two arcuated lobes, from the right and left 

 angles of which two very short, flat, setose tentacula spring; 

 these vary, being in some animals more cylindrical : a little be- 

 hind their origin the large subrotund eyes are seen at rather the 

 internal bases ; these appear dull, being imbedded within the 

 skin. Beneath the neck -veil a narrow, flat, rather taper, grooved 

 muzzle issues, within which the buccal mass, with high powers, 

 may be seen in action, though neither the tongue nor the corneous 

 plates could be detected : the muzzle rests on the foot, which 



