CANCELLARIID.E. 243 



both continents. Another high-northern species, V. 

 lanigera of Moller (V. elongata, Forbes and Goodsir), 

 ]ias been fonnd by Mr. Searles Wood, according to 

 Forbes, in the Mammalian Crag at Thorpe. 



Family XXIII. CANCELLAPJ'ID^, {Cancel- 



lariadce) Forbes and Hanley. 



Body regularly spiral : mantle faxing an incomplete or ru- 

 dimentary branchial fold : head snout- shaped, and short : 

 proboscis long, retractile : tentacles awl-shaped : eyes on stalks 

 amalgamated with the tentacles at their outer base : foot lan- 

 ceolate, comparatively small : gills double. Sexes separate. 



Shell turbinated, more or less umbilicate : spire erect : 

 mouth grooved within at the base, and having continuous lips : 

 pillar plaited, or else furnished with a single fold or a tuber- 

 cle : operculum horny, not spiral, but increasing by semielliptic 

 oblique layers. 



In TroscheFs classification of the Gastropoda, founded 

 on the structure of their lingual apparatus, the present 

 family is arranged alongside of the Velutinidce, Sigare- 

 tidce, and Naticida? ; the same natural position is in- 

 dicated by their shells. But it is questionable whether 

 the odontophore affords constant characters to distin- 

 guish species ; for, in the supplement to his excellent 

 and elaborate treatise, the learned German Professor 

 notices a difference as to the development of the notches 

 in the teeth of certain specimens of Trichotropis borealis. 

 The typical genus, Cancellaria, is not British, although 

 abounding elsewhere in recent and fossil species of ele- 

 gant shape and beautiful sculpture. It is said to have 

 no operculum. So little, however, is known of the 

 animal of that genus that I cannot compare it with the 

 soft parts of Trichotropis ; and I w r ill therefore omit this 

 part of the description, in treating of the latter genus. 



m 2 



