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A few specimens showing traces of a similar surface ornamentation, 

 which are therefore possibly referable to this species, were collected at 

 Little Black Island, Lake Winnipeg, by J. B. Tyrrell in 1889, and by D. 

 B. Dowling and L. M. Lambe in 1890. One of these is a rough cast of 

 one side of the greater part of the outer volution (with a small portion of 

 the test preserved) about twenty-seven inches in length, as measured 

 along the middle of the side and following its curve, the septate portion 

 occupying about nine inches thereof posteriorly. This specimen, which 

 appears to have been abnormally compressed laterally, is about four 

 inches and three-quarters in its dorso-ventral diameter posteriorly and 

 about five inches anteriorly. It is regularly curved posteriorly, but 

 straighter anteriorly. Another is a rough cast of one side of an almost 

 straight but very slightly curved and much more slender specimen, which 

 is sixteen inches in length, as measured along the middle of the gentle 

 curve of the side, and two inches and three quarters in its dorso-ventral 

 diameter at about the midlength. A third is a mould of the exterior of 

 one side of the outer volution, upwards of six inches in diameter, and 

 shewing posteriorly impressions of fine transverse ribs, but much worn 

 and indefinite anteriorly. In another large fragment from this locality 

 the ribbing is unusually fine and the ribs average scarcely a millimetre in 

 breadth. All four, however, are much too imperfect and too badly 

 preserved to be satisfactorily determined. 



In addition to these, a few coarse and very imperfect casts of large 

 nautilian or gyroceran shells, which represent at least two and perhaps 

 more species, but which shew no indications of the position of the 

 siphuncle, nor any trace of the surface markings, and which cannot at 

 present be determined even generically, were collected at Dog Head 

 by Mr. Weston in 1884, and at Clark's Point and the mouth of the 

 Little Saskatchewan by Mr. Dowling in 1890. In most of these speci- 

 mens, if not in all, the sutures of the septa appear to curve concavely 

 backward on each of the sides, and probably form single, convex saddles 

 on the periphery, whereas in Trochoceras McCharlesii the sutures curve 

 convexly forward on the sides, and concavely backward on the periphery. 



