apart on the dorsum, and seven mm. on the venter, near the body cham- 

 ber, that the siphuncle is placed about half-way between the centre and 

 the venter, and that it is almost cylindrical, but slightly constricted at or 

 near each of the septa." 



Little Black Island, Lake Winnipeg, J. B. Tyrrell, 1889, two speci- 

 mens, and T>. B. Dowling and L. M. Lambe, 1890, two specimens. 



"These a'e referred to the genus Eurystomites, Schroder, on the 

 authority of Professor Hyatt, to whom one of the most perfect specimens 

 was sent for examination. In a letter recently received. Professor Hyatt 

 says of this specimen : ' The suture has a decided broad ventral lobe 

 and lateral lobes, and internally there is an impressed zone showing a 

 true close coiled nautilian form. The siphuncle is ventrad of the centre, 

 small and with delicate walls.' Nautilus Hercules of Billings, from the 

 Hudson River formation of the Island of Anticosti, which Hyatt doubt- 

 fully refers to the genus Litoceras, has a broad flattened venter and a 

 similar kind of coiling to that of E. plicatus, but both sides of the outer 

 volution of Nautilus Hercules are distinctly angular." 



DiscocERAS Canadense. (N. Sp.) 



Plate 22, figs. 3 and 3a. 



Shell discoidal, whorls three, coiled apparently in the same plane, or 

 very nearly so, in close contact but with little or no overlapping, the 

 outer one, where least distorted, slightly compressed at the sides and 

 rounded on the venter or periphery, so that the outline of a transverse 

 section would be broadly elliptical or nearly circular : umbilicus wide, 

 open and shallow, exposing nearly the whole of the inner volutions : body 

 chamber occupying about one-half of the outer volution. 



Surface of the two outer volutions marked by rather prominent simple 

 ribs or rib like folds, which curve obliquely backward and form a series 

 of deeply angular sinuses on the venter, and are separated by rather 

 broad, concave grooves. Inner volution nearly smooth, marked only 

 with fine and crowded transverse striae. 



Siphuncle placed near the margin of the inner and probably dorsal 

 side : sut;ures of the septa unknown. 



Maximum diameter of the most perfect specimen collected : two inches 

 and a half. 



Little Black Island, Lake Winnipeg, J. B. Tyrrell, 1889, one specimen ; 

 and Commissioners (or Cranberry) Island, D. B. Dowling, 1890, the 

 specimen figured. The slight lateral flattening observable on both of 

 them is apparently abnormal and probably due to compression subsequent 

 to tlieir fossilization. 



