UMAX. 139 



idly increasing, the last broad bolow, flattened ; aperture obliquely oval, the 

 tennination of the peristome membranous, that of the columella slightly re- 

 flected, iiivinj; the imi)ression of a imnctiform i)erforation. Greater 



'^ ° . ' . ^ Fig. 54. 



diameter 7^, lesser 5 mill. ; height, 3 mill. 



Allied to V. pellucida, but with less broad spire and differing w^ 

 in the perforation. (Morelet.) 



Vitrina exilis, Mouklet, Journ. de Conch., VII. 8. — Pfeiffkk, 

 Mon. Hel. Viv., IV. 799 (1859). ^- ««'^"- 



A Kamtschatka species. Petropaulauski (Dall), Ounalaska (Cooper, as fel- 

 lucida ? Am. Journ. Conch., V. 200). 



Jaw and lingual membrane as usual in the genus, the former with ends some- 

 what recurved as in Zonites arhoreus. 



Vitrina exilis has about 37 — 1 — 37 teeth on its lingual membrane, with 7 per- 

 fect laterals. I have given on PI. II. Fig. B, one central, lateral, and marginal. 



Fossil Species of Vitrina. 



Vitrina obliqua, Meek & Hayden, Proc. Phila. Acad. Nat. Sci. 1857, 134. 



LIMAX, Linn. 



Body subcylindrical, lessening towards the posterior extremity, which termi- 

 nates in a point. Back with a carina or keel when contracted, convex when 

 extended. Integuments with longitudinal elongated glands, and anastomosing 

 furrows arranged in the same manner upon both sides. Mantle small, anterior, 

 oval, marked with fine concentric striae or prominent wrinkles, unattached and 

 free at the front and sides, but connected with the body at its posterior part, 

 and containing in this part a testaceous rudiment or shell. Base of foot not 

 expanded at margin, having a narrow locomotive disk running longitudinally 

 along its centre and separated from the sides by a well-defined line or furrow. 

 Respiratory orifice near the right posterior margin of the mantle, large. Anal 

 orifice immediately adjacent to, but a little below and anterior to the respira- 

 tory orifice, with a cleft or fissure through the mantle from the orifice to its 

 edge. Orifice of organs of generation near, and immediately behind, the right 

 eye-peduncle (Vol. III. PI. LXV.). 



Testaceous rudiment thin, concentrical, not spiral, covered above with a thin 

 and transparent periostraca, below smooth. 



Jaw arcuate, with slightly attenuated but blunt ends ; yj- 55 



anterior surface smooth, cutting margin with a decided 

 beak-like median projection. There is often a central ver- 

 tical carina to the jaw. Tlie ends are often more pointed 

 than in the jaw figured. I have examined the jaw of all J &w of Umax. 

 our species. 



The dentition of Limax is nearly allied to that of Zonites. The lateral teeth 



