42 CONCHOLOGIA CEST RICA: 
Station, under logs and loose bark. Chester County ; 
frequent. 
H. electrina, GouLp. 
Helix electrina, Gould, Invert., Mass., 1841. 
H. electrina, 
[B. & B.] 
Fig.60. last rapidly enlarging; spire depressed; 
Shell very thin, pale; whorls 3%, the 
aperture rounded; peristome simple, acute ; 
lip not flexuous; umbilicus very narrow, 
and deep. Hy 2, W. 4, mull? 
Station, in company with the preceding. 
ete cori rare. 

H. arborea, Say. 
Helix arboreus, Say, Nich.-Encyc., Amer. Ed., 1817. 
H.arborea. — Shell much depressed, thin, shining, amber- 
Bi aa colored; whorls 4%, increasing regularly ; 
a _ umbilicus moderate, deep; lip slightly flexu- 
ous; lines of growth indistinct. H. 2%, W. 
5, mill. 
Station, under decayed wood, and rubbish. 
Chester County ; abundant. 


H. hydrophila, INGALLS. 
Helix hydrophila, Ingalls, in collection unpublished. 
st He ates Shell depressed-conical, thin, amber- 
Fig, 62, colored; whorls 4 to 4%; suture well 
impressed; umbilicus deep, crateriform ; 
aperture lunate, sub-deflected; lip thin, 
sub-angular. H. 3, W. 6, mill. 
Station, under logs, and boards, near 
the water. Schuylkill tide marsh, Phila- 

delphia. 
Ops. ie prefer to keep this distinct from H. nitida, 
Mull., of Europe. 
