332 A MANUAL OF AMERICAN LAND SHELLS. 



FOSSIL SPECIES OF PUPA. 



Fupahelicoides, Meek and Hayden, Proc. Acad. Nat. Sci. Philad., viii, 118. 

 Pupa vefusta, Dawson, Geol. Soc. Proc, 18.^>2, ix, 60, pi. iv (Dendropupa, Owen). 

 Pupa Vermtlionensis, coal of Illinois (see Silliman's Amer. Journ. of Science for Aug., 

 1872). 



VEKTIGO, Mull. 



Animal as in Pupa, but tentacles wanting. 



Shell deeply rimate, ovate, apex acuminate, obtuse ; whorls 5-6, the 

 last rounded ; aperture semi-oval, with 4 to 7 folds ; peristome scarcely 

 expanded, white-lipped. 



The distribution of the genus is world-wide. 



Jaw more or less arched, ends but little attenuated, blunt; anterior 



surface with delicate vertical striss; cutting margin with a more or 



less developed median projection. I have given Fig. 359, copied from 



PIG. 359. that of Morse. In the L. & Fr.-W. Sh. N, A., I, will be 



'T'TnTTTx found other figures of jaws, showing the variations in 



outline found in the genus. I have personally exam- 



Jaw of Vertigo 



ovata. (Morse.) incd the jaw in none of our species. 



For the characters of the lingual dentition I am also entirely de- 

 pendent on Morse. 

 Fig. 360 shows the general arrangement of the teeth on the mem- 

 YiG. 360. brane. The membrane is long and 



narrow. The central teeth liave a 

 base of attachment higher than 

 wide, subrectangular. The whole 

 ui)per margin is broadly reflected. 

 Lingual dentition of y«/-/iV7o oua<a. (Moise.) The rcflcction is Very short, and 

 bears three short, stout cusps, the central the longest, each cusp bear- 

 ing (I presume) a distinct cutting i^oint. The central tooth, in those 

 species whose dentition is known to me, is as large as the laterals, and 

 not smaller, as seems to be the rule in our species of Pupa. The 

 lateral teeth are like the centrals, but asymmetrical. The reflected 

 portion is small, tricuspid, or bicuspid. The marginals are wide, low, 

 with a broad, irregular, denticulated reflection. 



Subgenus ISTHMIA, Gray. 

 Shell dextral. 



'Vei'tig:o milium, Gould. 



Shell very minute, subcylindrical, diminishing equally to both ex- 

 tremities ; epidermis darl^-amber or chestnut color ; whorls 5, rounded, 



