HELIX. 219 



This species closely resembles H. ruderata, Studer ; 

 and Prof. Adams declares that he cannot detect any 

 difference in the two. I have found no difficulty in dis- 

 tinguishing them at first sight, but have not seen a 

 sufficient number of specimens of the foreign species to 

 enable me to speak confidently on the subject. It must, 

 of course, be considered a doubtful species. 



56. HELIX LIMATULA, BlNWEY. 



Plate XXX. Figueje 2. 



H. testa parva, orbiculato-depressa, umbilicata, tenui, 

 albida ; anfractibus quatuor convexis, oblique et minutis- 

 sime striatis ; apertura sub-circulari, tenui, acuto. 



SYMONYMS AND EEEEEENCES. 



Selix limatula, Ward, MSS. 



BiNNEY, Boston Joiirn. Nat. Hist. III. 434, pi. 21, f. 2. 

 Pfeiffeb, Monog. Helic. Viv. I. 113. 



DESCRIPTION. 



Animal not observed. 



Shell small, depressed ; epidermis whitish, immac- 

 ulate ; suture distinctly impressed ; whorls more than 

 four, convex, with very fine, oblique, parallel striae, 

 which become obsolete on the base ; aperture sub-circu- 

 lar, slightly modified by the penultimate whorl ; hp thin, 

 acute ; umbihcus rounded, large and deep, not exhibit- 

 ing all the volutions. 



Greatest diameter about one-fifth of an inch. 



