332 HELICID^. 



ception of P. milium, and is most readily distinguished 

 by its short, conical form. The five specimens examined 

 all presented the crowded, thimble-like impressions, un- 

 der a magnifying power of twenty diameters. I think it 

 is the only American species which has a tooth revolving 

 within the shell, on the penultimate whorl. — [«.] 



b. Tentacles apparently two only. Vertigo. 



9. VERTIGO GOULDII, BiNNEY. 



Plate LXII. Figure 2. 



V. testa minuta, ovato-cylinclracea,sub-castanea; anfract- 

 ibus plusquam quatiior ; apice obtuso ; apertura sub-cordata, 

 bilobata, dentibus quinque armata ; labro sub-refle,\o. 



SYNONYMS AND KEFEKENCES. 



Fiipa Gouldii, Binney, Proc. Bost. Soc, 18J3. I. 105. 



Gould, Boston Journ. IV. 352, pi. 16, f. 9. 

 Pfeiffer, Monog. Helii;. Viv. II. 358. 



DESCRIPTION. 



Animal with two tentacles only ; black above, foot 

 gray, tapering posteriorly, and rounded at the extremity ; 

 carries the shell at an angle of about forty-five degrees. 



Shell light chestnut, cylindrical ovate ; whorls rather 

 more than four, ventricose, the last occupying nearly one- 

 half the length of the axis ; aperture lateral, composed 

 of two unequal curves meeting in the centre of the outer 

 lip, with five prominent, white teeth ; namely, one upon 

 the transverse margin, two upon the uiubilical margin. 



