thickened within the apertuie thru which may be seen 2 to 4 

 rows of 5 or 6 teeth each, radiating from the axis towards the 

 circumference, upon the base of the outer whorl; teeth situated 

 far within, and last row not usually visible from the aperture; 

 diameter 3, height 1.5 mm. 



Hartland, Vermont, rare. Maine; New York; Ohio. 



14 Macrocyclis concava 



Diameter 12 to 15 mm, whorls 5, superior part of last one 

 flattened towards the mouth, well rounded beneath; light horn 

 color or greenish, but almost white; slightly striate, suture well 

 impressed, umbilicus rather wide and deep. 



Hartland, Vermont, rare. Maine, Iowa, Georgia, Mississippi. 



15 Helix alternata 



Hartland, Vermont, common. Also the carinated form. 



16 Helix striatella 



Hartland, Vermont, abundant. Widely distributed. 



Diameter 5, height 2.5 mm; depressed convex, nearly disc- 

 oidal; whorls less than 4, with delicate oblique striae; suture dis- 

 tinct; aperture rounded, transverse; umbilicus very large, shal- 

 low; light horn color. 



17 Helix asteriscus 



Diameter 1.5, height .75 mm; elevated, planorboid; whorls 4, 

 very convex; suture deep; surface with 25-30 very oblique, thin, 

 raised ribs, between which it is finely striate; umbilicus moder- 

 ately large, showing all the volutions; color light brown. 



Hartland, Vermont, very rare; Maine; Massachusetts; Ta- 

 coma, Washington. 



18 Helix labyrinthica 



Hartland, Vermont, abundant. Texas; Arkansas. 



19 Helix monodon 



Hartland, Vermont, abundant. Canada; Texas. 



20 Helix tridentata 



Hartland, Vermont, rare. Canada, south thru eastern U. S. 



21 Helix albolabris rosa 



Hartland, Vermont (C. 0. Tracy). A beautiful color form. 



22 Helix m'.lchella 



Shell widely umbilicated, depressed, slightly convex above, 

 thin, transparent; epidermis colorless; whorls 4, very minutely 

 striated, the last large and spreading at aperture like a trumpet; 

 aperture orbicular, a little dilated; peristome much thickened, 

 white, reflected, making nearly a continuous circle, ends ap- 

 proaching; umbilicus large, exhibiting all the volutions; greater 

 diameter 3, lesser 2.5, height 1.5 mm. 



Hartland, Vermont, rare. A circumpolar species, common to 

 the three continents. Los Angeles, Cal. (R. E. C. Stearns). 



23 Cionella snbcylindrica 



Shell oblong-oval, thin, polished, transparent; whorls 6, 

 slightly convex, apex obtuse, sutures well marked; aperture oval, 

 longitudinal, lip thickened but not reflected; umbilicus impervi- 

 ous; color bright amber; length 7.5, diameter 2.5 mm. 



