COLIMACEA. MOLLUSCA. HELIX. 177 



Zurama pulchella, LEACH; MoUu*e. t 108. GRAY ; Edit, of Turton't Brit. Land., 



and FT. Water Shells, 141. 

 Lucena pulchella, HARTMANN ; t. 1, f. 6. 



Shell minute, semi-transparent, white, or very light horn-color, 

 thin, depressed ; whorls four, very minutely marked with lines of 

 growth, the last spreading at the mouth like a trumpet ; suture 

 deeply impressed ; aperture circular, the lip very nearly sur- 

 rounding it, much thickened, white, and reflected ; umbilicus 

 large, exhibiting all the volutions within. Diameter one tenth of 

 an inch. 



Animal pale, semi-transparent. 



Rather common in the vicinity of Boston, under stones in rich 

 soil, and about decaying stumps. It is probably abundant in all 

 parts of this State, and has been noticed in Ohio, and on the 

 banks of the Missouri as high up as Council Bluffs. 



This very minute snail is a very beautiful shell when examined by 

 a magnifier. It has rather the external characters of CyclosLoma than 

 of Helix. It agrees with the H. pulchella of Mu'ller in all respects, 

 except that it is never supplied with the sharp, parallel ribs which are 

 frequently found on the foreign specimens, though by no means con- 

 stantly. It is thought by some to have been introduced from Europe. 

 But, as Dr. Binney remarks, " it does not seem possible that so small 

 an animal, if naturalized since the arrival of Europeans, could have 

 been able to penetrate to the remote points in the interior of the con- 

 tinent where it is now found." 



HELIX ALTERNA'TA. 



Shell orbicular, depressed, fawn-colored, barred with oblique, 

 zigzag lines of dusky ; whorls five or six, with prominent wrinkles 

 at the lines of growth ; lip simple ; umbilicus large and deep. 



FIGURE 114. 

 State Coll., No. 99. Soc. Cab., No. 1045. 



Helix alternate, SAY ; Nicholson's Encyc., (Amer. ed), iv. pi. 1, f. 2. Journ. Acad. 



Nat. Sc., ii. 161. FKRUSSAC ; tiist. Wat. dts Moll., pi. 79, f. 8, 9, 10. DESHAYES ; 



Encyc. Meth., Vers, ii. 219. BINNEY ; Bost. Journ. JWrt. Hist., iii. pi. 32. 

 Helix scabra, LAM.; An. sans Vert., viii. 66. 



Helix radiata, GMKLIN ; Syst., 3674, No. 73. LISTER ; Conch., t. 70, f. 69. 

 23 



