PUPA. 249 



description in the ^ Fauna Suecica ^ of the form of the 

 mouth C^^ ovato-acuminata^, mucrone obtuso^^) agrees 

 better with this species than with P. marginata, to which 

 so many conchologists have attached the specific name 

 of muscorum. According to the strict rules of scientific 

 nomenclature, the present species (if it is not the Helta; 

 muscorum of Linne) ought to bear the name of cylin- 

 dracea, which was given to it by Da Costa in 1778, long 

 before either of Draparnaud^s publications; but I fear 

 justice must in the present instance cede to convenience, 

 as the name of umbilicata is so universally used. Da 

 Costa^s name appears to have shared the same fate as 

 the early leaf, — 



" Ut silvce foliis pronos mutantur in annos, 

 Prima cadunt ; ita verborum vetus interit setas, 

 Et juvenum ritu florent modo nata vigentque." 



C. Shell short, cyhndrical : spire blunt : mouth semioval, some- 

 times furnished with one or two tubercular teeth : outer 

 lip strengthened by a thick exterior rib. 



4. P. margina'ta"^, Draparnaud. 



P. marginata, Drap. Tabl. Moll. p. 58, and Hist. Moll. p. 62, pi. iii. f. 36-38. 

 P. muscorum, F. & H. iv. p. 97, pi. cxxix. f. 8, 9. 



Body narrow and somewhat rounded in front, more slender 

 behind, lustrous, dark-grey with a brownish tint, finely speckled 

 with black, and of a much lighter shade on the under part ; 

 shghtly but closely tuberclcd : laantle as in the last species, 

 but the milk-white specks are larger : tentacles thick, opaque, 

 dusky, rounded at their points ; upper pair similar to those in 

 P. umbilicata, with subglobiilar bulbs ; lower pair somewhat 

 diverging from each other, conical, smooth, rather opaque, and 

 nearly black : foot not fringed, narrow but somewhat rounded 

 in front, broader behind, and ending in a triangular tail. 



Shell subcylindrical, rather solid for its size, nearly opaque, 

 not very glossy, pale yellowish-brown or horncolour, faintly 



* Margined. 



M O 



