40 LITTORINID.E. 



Sutton. Its foreign known or supposed distribution is 

 southern and limited, as follows : — Gulf of Lyons (Mar- 

 tin); Spezzia (Doria and J. G. J.); Ajaccio (Requien); 

 Naples (Tiberi); Teneriffe (M f Andrew). 



R. proximo, appears to be a rare as well as " critical ; ' 

 species. Besides its affinity to R. vitrea, it is nearly 

 related to the variety arctica of R. striata. In the last- 

 named species, however, the texture and sculpture of 

 the shell are coarser, the spire is pointed and not trun- 

 cated, and the suture is less deep and not so oblique. 

 The present species may be distinguished from R. vitrea 

 by its being striated and never glossy. May one be the 

 male and the other the female of the same species ? 



It is probably the R. pupoides of Requien. I de- 

 scribed it about twenty years ago in the ' Annals of 

 Natural History ' as R. striatula, not remembering that 

 the name had been preengaged for a supposed Linnean 

 species. 



20. R. vi'trea*, Montagu. 



Turbo vitreus, Mont. Test. Br. p. 321, t. 12. f. 3. B. vitrea, F. & H. 

 iii. p. 125, pi. lxxv. f. 5, 6. 



Body white, and appearing as if veined, with a frosty hue : 

 snout short, cloven at the extremity, fleshcolour: tentacles thread- 

 shaped, long and compressed, setose at the tips only, and ser- 

 rated at the outer bases: eyes conspicuous, placed on small 

 bulbs or eminences : foot double-edged in front and indented 

 so deeply as to form two distinct broad lobes, rounded behind : 

 no appendage observable. 



Shell nearly cylindrical, thin, semitransparent, and of a 

 glassy lustre : sculpture none, examined with a hand-lens ; 

 but under the microscope or even a Coddington lens the sur- 

 face exhibits extremely fine regular and close-set spiral striae : 

 colour of live or fresh specimens pale yellowish-white, which 

 soon becomes bleached by exposure to the air : spire elongated 

 and slender, ending rather abruptly in an obtuse point : whorls 



* Glassy. 



