HELIX. 229 



61. HELIX SUB-PLANA, BINNEY. 

 PLATE XXXIII. 



H. testa discoidea, fuliginosa, nut corneo-rufescente, 

 nitente ; spira depressa ; anfractibus quinque, vel sex ; 

 apertura semilunari, transversa ; labro simplici, acuto ; basi 

 piano ; umbilico parvo. 



SYNONYMS AND REFERENCES. 



Helix sub-plana, BINNEY, Boston Journ. Nat. Hist. IV. 2-11. 

 PFEIFFER, Monog. Helic. Viv. 112. 



DESCRIPTION. 



SHELL flattened, planulate above and beneath ; epi- 

 dermis brownish or smoky horn-color, shining ; whorls 

 five and a half, those nearest the apex striated trans- 

 versely with very minute and delicate wrinkles ; suture 

 distinct, not much impressed ; aperture transverse, not 

 expanded, the plane of the aperture making nearly a 

 right angle with the plane of the base of the shell ; lip 

 simple, thin, acute ; base flattened, umbilical region a 

 little impressed ; umbilicus small, round, and deep, not 

 exhibiting the volutions. 



Greatest diameter less than three-fourths of an inch. 



GEOGRAPHICAL DISTRIBUTION. Found hitherto only 

 in the mountainous region of Eastern Tennessee. 



REMARKS. The only American species which this 

 shell can be said to resemble is Helix inornata, which in 

 size and color is quite like it, and at first sight may be 

 taken for it. It differs from it in the following parti- 



