3 
thickened within the aperture 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. O. Tracy). A beautiful color form. 
22 Helix nulchella 
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. BE. C. Stearns). 
23 Cionella subevlindrica 
Shell oblong-oval, thin, polished, transparent: whorls 6, 
slightly convex, apex obtuse, sutures well marked; avertvre oval, 
longitudinal, lip thickened but not reflected; umbilicus impervi- 
ous; color bright amber; length 7.5, diameter 2.5 mm. 
