WHiTEAVES ] DEVONIAN FOSSILS OP MANITOBA, ETC. 329 



and obtuse at its apex : base deeply umbilicated. Volutions seven or 

 eight, the earlier or apical ones depressed convex, the later or lower whorls 

 of the spire moderately convex but somewhat compressed laterally, — 

 the outer volution rounded, slightly inflated and gradually expanding, 

 more than twice as broad as high : umbilicus occupying nearly one-half 

 of the total diameter of the base, though the umbilical margin is rounded 

 and very indefinite : suture deeply impressed : aperture apparently sub- 

 circular. 



Surface marked by numerous minute spiral raised lines, which are 

 crossed by equally minute but much more numerous and closely disposed 

 flexuous transverse ridges. Under a lens, these latter are seen to curve 

 gently backward on each side of the periphery, where each one forms a 

 shallow sinus, and to be tuberculated at the points where they pass over 

 the spiral lirula?. 



The approximate dimensions of the specimen represented by figs. 12 

 and 12a, which is a remarkably perfect cast of the interior of the shell, 

 are as follows, as measured in the centre of the dorsal surface : entire 

 height, 18-75 millimetres; height of last volution, 8-7 mm.; breadth of 

 the same, 18 mm. 



Pentamerus Point, Lake Manitoba, J. B. Tyrrell and J. F. Whiteaves, 

 1888 : seven specimens. Dawson Bay, LakeWinnipegosis, — on the south- 

 west shore two miles west of Salt Point, — on the west shore, at the first 

 small point north of the Red Deer River, at the south end of Rowan 

 Island, — and on three small islands in the southern portion of the bay, J. 

 B. Tyrrell and D. B. Dowling, 1889 : a few specimens, some with consider- 

 able portions of the test preserved, from each of these localities. 



This very distinct species is evidently congeneric with the Straparollina 

 asperostriata, S. Circe and S. Eiirydice of Billings*, from the Black River 

 limestone of Paquette's Rapids, on the Ottawa River. It is not very 

 dissimilar, in general form, to S. Eurydicr, but its sculpture is more like 

 that of (S". asperosfri((ta. The genus is represented in the Lower Cambrian 

 by the S. remota, Billings, of the Olenellus zone of Newfoundland, in the 

 " Quebec Group " of that island by »S'. pelagica, Billings, and in the Black 

 River limestone of Canada by the three species already enumerated. In 

 the writer's judgment, the " Straparolhis Daphne " of Billings, from the 

 Guelph limestone of Ontario, is also a Strajiarollina. 



*Deseribed in the Can. Nat. & (ieol., 1860, vol. V, pp. 161-02, and figured on p. 144 

 of the Geol. Canada (1863). 



