HELIX. 019 



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, BlNNEY. 



PLATE XXX. FIGURE 2. 



H. testa parva, orbiculatodepressa, umbilicata, tenui, 

 albida ; anfractibus quatuor convexis, oblique et minutis- 

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



SYNONYMS AND REFERENCES. 



Helix limatnla, WARD, MSS. 



BINNEY, Boston Journ. Nat. Hist. III. 434, pi. 21, f. 2. 

 PFEIFFER, Monog-. Helir. 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 ; lip thin, 

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

 ing all the volutions. 



Greatest diameter about one-fifth of an inch. 



