MOLLUSCA OF MICHIGAN— WALKER. 475 



Alt. 13, greater diam. 26, lesser 22 mm. 

 Belix fuliginosa, Griffith, Bost. Jom\ Nat. Hist., III., 417, pi. XXIV, 

 (1840). 



Zonites , W. G. Bimiey, Man. Am. Land Shells, 207, fig. 217, (1885). 



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



; Miles, Rep Geol. Siirv. Mich.,' 235, (1861). 



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



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



Zonites fuliginosus, Walker, Rev. Moll. Fauda Mich., 16, (1894). 



Apparently rare and local. Reported from Ottawa, Kent, Genesee, Tus- 

 cola, Lapeer, Washtenaw and Monroe counties, which indicates a range 

 across the southern part of the state. 



OMPHALINA INORNATA (Say). 



Shell depressed; light yellowish horn-color, smooth, shining, 

 obscurely striate; whorls 4^; suture sHghtly impressed; aperture 

 transverse, shghtly obhque, broader than high, with a white, 

 callus deposit just within the margin; lip thin, acute, its ends 



somewhat converging, the basal extremity impinging on the 



Fig. 33. small umbilHcus; base somewhat flattened, indented in the centre. 

 ""(bE?)' Alt. 8i, diam. 15 mm. 

 Helix inornata, Say, Jour. A. N. S. P., IL, 371, (1821). 

 Zonites inornatus, W. G. Binney, Man. Am. Land Shells, 217, fig. 229, (1885). 

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



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



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



This species, after escaping observation for forty years, has recently been 

 discovered by Mr. W. Miller, who has submitted 'specimens found near 

 Grand Rapids. He also reports it from Hart, Oceana county, but the 

 specimens from the latter locality have been lost or mislaid, and conse- 

 quently have not been authenticated. 



It is a w^ell marked species and easily distinguished from 0. fuliginosa by 

 its smaller size and minute umbillicus. 



Genus VITRINA Draparnaud. 



Shell external, imperforate, pellucid, glossy, depressed: spire short; whorls 

 2-3, rapidly increasing, the last wide; aperture large; peristome thin. 



Animal heliciform, obtuse before, pointed behind- 

 mantle, posterior with an anterior prolongation cov- 

 ering the back, and with a process or prolongation 

 which is reflected backward upon the shell. A dis- 

 tinct locomotive disk. No caudal mucus pore. 

 04 A • 1 f yv • Respiratory orifice subcentral, on the right side of 

 ^^' ' (BinneyO * ^^"^' the mantle, under the peristome of the shell. Anal 

 orifice contiguous to the respiratory orifice. 



Jaw highly arched, ends acuminated, blunt; cutting margin 

 with a prominent, bead-like median projection. Dentition; 

 centrals with a quadrangular base of attachment, longer than 

 broad, tricuspid; laterals arranged in straight transverse rows, 

 Fi???- ., asymmetrical; marginals with sole-shaped base of attachment 



Jaw of V.hmpida. i 1 j -i -n 1 jj- - , 



(Binney.) and aculeate, bind cuttmg-pomts. 

 45 



