193 



Surface markings of the later volutions consisting of a broad, flat slit- 

 band near their midheight or midlength, and of low, rounded, riblike 

 plications or wrinkles of growth, which converge very obliquely backward 

 to the slit-band. 



The foregoing description is based upon two large specimens, with 

 considerable portions of the test preserved, collected at Little Black 

 Island (not at Berens or Swampy Island proper)* by D. B. Dowling 

 and L. M. Lambe in 1890. The larger of these specimens, which is 

 figured, is fully eight inches in length and very much flattened in the 

 dorso-ventral direction. The smaller, which is upward of seven inches 

 in length, is slightly compressed in the same direction. They both differ 

 from Murchisonia inajor, Hall,t in their very much larger size, and from 

 M. teretiformis, Billings,]; in their much less ventricose volutions, more 

 lightly impressed suture, and in their coarser and more rib-like wrinkles 

 of growth. 



Comparatively small specimens, which are apparently referable to the 

 same species and which rarely exceed four inches and a half in length, 

 had previously been collected at two localities on the JSelson River, 

 Keewatin, by Dr. R. Bell in 1879; at Dog Head and Jackfish Bay, 

 Lake Winnipeg, by T. C. Weston in 1884; at Little Black Island by 

 J. B. Tyrrell in 1889; at Little Tamarack and Commissioners' islands 

 and at a point off Moose Creek, near Snake Island, Lake Winnipeg, by 

 D. B. Dowling in 1890. All of these specimens are slightly compressed, 

 and most of them are mere oasts of the interior of the shell. 



SoLENOSPiRA PAGODA (Salter), var. occidentalis. 



Shell resembling S. pagoda (the "Eimema ? pagoda of Salter) || in 

 shape, and in the circumstance that its volutions are encircled with four 

 spiral ridges, but differing therefrom in its much greater size and propor- 

 tionately broader slit-band. 



The type of ;S^. pagoda, as figured by Salter, is twenty-four millimetres 

 in length, and its outer volution is nearly eight mm. broad. In the only 

 specimen of the var. occidentalis known to the writer, the length is about 

 fifty-nine mm., the breadth of the last volution nineteen mm. and a half, 

 though the whole specimen is laterally and abnormally compressed, and 

 the slit-band, near the aperture, is three mm. and a half broad. 



* Little Black Island is very close to Berens Island, and connected with it by a bar 

 or reef. 



t In Foster & Whitney's Report on the Geology of the Lake Superior Land District, 

 pt. 2, p. 209, pi. 26, figs. 1, a-c. 



J Geological Survey of Canada, Rep. Progr., 1853-56, p. 298. 



_|| Geological Survey of Canada, Canadian Organic Remains, Decade 1, 1859, p. 30, pi., 

 6, fig. 5. 



5 



