20 CONTRIBUTIONS TO CANADIAN PALyEONTOLOGY. 



ilaximum breadth, four millimotres : height or depth, about two. 



Old Man Eiver, two miles above Eye-Grass flat, G. M. Dawson, 

 1881 ; St. Mary Eiver Series. 



The only specimen collected is a well preserved cast of the interior, 

 with nearly all the test preserved except that which originally formed 

 the outer margin of the aperture. In the cast this margin appears to 

 be unbroken, but still it is possible that the specimen may not represent 

 a fully adult shell. The species is referred to Klein's genus Anchistoma 

 in the sense in which Stoliezka and Fischer use the word, also on account 

 of its ap^jarent generic affinities with the three species of Anchistoma 

 described l.y Stoliezka in the " Cretaceous (Gastropoda of Southern 

 India," though it may be a small Poli/gyra. The upper portion of the 

 aperture of the A. Arrialoonnse of Stoliezka seems to be singularlj' like 

 that of the present species. 



Thatjjlastus LiMNyEiFORiiis, Meek and Haj-den. 



Plate 3, fig. 3. 



Bulinnis Umn:riform-h, Meok and Hayden. 18.56. Proc. Ac. Nat. Sc. Phil., vol. 



yiii., p. 118. 



Bulimus Nchrascermls, IMeek aad Hayden. llj. 



TIiawwMtvs Jrmrudformis, Meek. 1876. Rep. U. S. Geol. Surv. Terr., vol. IX., p. 

 553, pi 44, flgs. 8, a, b, c, d. 



Eosebud Eiver, Township 27, Eange 25, west of 4th Principal Meri- 

 dian, one perfect and exquisitely preserved sjjecimen, also, Three Hills 

 Creek, Township 30, Eange 23, west of 4th Meridian, a few examples 

 associated with C'ampeloma producta White; at both localities collected 

 by Mr. J. B. Tyrrell in 1884. 



The dimensions of the specimen from the Eosebud Eiver, which is 

 of average size, are as follows: length, twenty-four millimetres: maxi- 

 mum breadth, nine mm. : length of last whorl, as measured near the 

 aperture, twelve mm. 



Althougli the specimens collected by Mr. Tyn-ell are nearly twice 

 the size of Meek's types and have a slightly more produced spire, they 

 agree so closely in every other respect with the description and figures 

 of T. Umrunformis that they are believed to be only a large local variety 

 of that species. 



