488 MICHIGAN SURVEY, 1905. 



^ QASTRODONTA LIQERA (Say). 



Shell perforated, orbicularly convex; yellowish horn-color, 

 shining; whorls 7, finely and closely striate; smooth below; spire 

 rather elevated, acute; suture not much impressed; aperture 

 semi-lunate, rounded; peristome thin, acute; aperture thickened 

 Fi^. 70. within by a white callus deposit on the base and outer wall. 

 (Binney ) Alt. 10, greater diam. 15, lesser 13 mm. 

 Helix ligera, Say, Jour. A. N. S. P., II., 157, (1821). 



Zonites ligerus, W. G. Binney, Man. Am Land Shells, 213, fig. 225, (1885). 



Helix ligera, Sager, Doc. H, Rep. Mich., 1839, 420, separate, 14. 



, Miles, Rep. Geol. Surv. Mich., 235, (1861). 



Mesomphix , Currier, Shell-bearing Moll Mich., 4, (1868). 



, DeCamp, Shell-bearing Moll. Mich., 5, (1881). 



Zonites ligerus, Walker, Rev. Moll. Fauna Mich., 16, (1894). 



Generally distributed in the southern part of the state. 



QASTRODONTA SUPPRESS A (Say). 



^r^^-> Shell subperforated, subconical; shining, pale yellowish 



(3 \^ ___-<; horn-color; spire somewhat pointed or obtuse; whorls 7-8,. 

 "^^^^^^^^ regularly and slowly increasing in diameter, striate above, 

 Fig. 71. smoother below; suture distinctly impressed; aperture trans- 



■(Binnej\)"' verse not much expanded; peristome simple, acute, thick- 

 ened by a white callus deposit within, with one or two lamelliform, parallel 

 teeth on the base; base flat, indented in the centre, near the aperture yel- 

 lowish white and opaque; umbihcus small and rounded in young shells^ 

 obsolete or diminishing to a mere perforation when adult. 



Alt. 5, greater diam. 8 mm. 

 Helix suppressa, Say, New Haven Diss., II., 229, (1829). 

 Zonites suppressus, W. G. Binnev, Man. Am. Land Shells, 225, fig. 241, (1885). 

 ^ Walker, Rev. Moll. Fauna Mich., 16, (1894). 



Apparently rare and local. Washtenaw, Genesee and Kent counties are 

 the only localities reported. 



Family LinACID/C. 



Animal naked, with a thin, internal, shelly, non-spiral plate; no cavidat 

 mucus pore; foot margin narrow. Jaw arched, without ribs, with a median 

 projection to the cutting edge. Lingual membrane with the rows of teeth 

 horizontal or slightly oblique; marginal teeth with narrow basal plates, 

 either unicuspid and thornlike, or bicuspid by elevation of outer on middle 

 cusp. 



Genus AQRIOLIflAX Morch. 



Animal shortly carinate behind. Jaw arcuate with slightly 

 attenuated but blunt ends; anterior surface smooth, cutting 

 margin with a decided beak-like projection. Central tooth of 

 Jaw rf^ "c^mits ^^^^^^^^ tricuspid; laterals bicuspid, in a straight row; marginals in 

 (Binney.) "oblique rows. Eggs orbicular. 



