212 HELICID^. 



spaces are seen to be well defined squares. Whorls five, 

 separated bj a deep suture, the outer one proportionally 

 large. Aperture nearly circular, a little angular at base, 

 modified by the preceding whorl ; lip acute, simple. 



Diameter half an inch ; axis a little over one-fourth of 

 an inch. 



Geograpuical Distribution. Brought by the U. 

 S. Exploring Expedition from Puget Sound, Oregon. 



Remarks. Much like H. concava, Say, which, how- 

 ever, presents a very smooth surface, a smaller and less 

 circular aperture, an umbihcus much broader, and the 

 outer whorl increases less rapidly. I know of no Ameri- 

 can species which has the surface similarly decussated. 

 IT. intertexta is most like it in this respect. The speci- 

 mens are immature, and probably the lip may be some- 

 what reflected in adults. — [g.] 



63. HKLIX ALTERNATA, Sat. 

 Plate XXV. 



H. testa orbiculato-depressa, late et profunde umbilicata, 

 striis elevatis, obliquis, crebris, scabra ; albido et rufo 

 alterne colorata ; obscure fasciata ; apertura circulari ; 

 labro tenui, acuto. 



SYNONYMS AND BEFEBENCES. 



Helix alternata, Say, Nich. Encyc. IV. pi. 1, f. 2 ; Jourii. Acatl. II. ICl. 

 KiRTLAND, Ohio Report, 172. 

 Sagee, Micliigan Catalogue, 14. 

 BiNNEY, Boston Joiirn. Nat. Hist. III. 428, pi. 35. 

 Gould, Invertebrala, 177, f. 114. 



