WHITEAVE8.] DEVONIAN FOSSILS OP -MANITOBA, ETC. ol'i 



(S.) Pleukotomaeia INFHANODOSA. (N. Sp.) 



Plate 41, tigs, i, 2a and 3. 



Shell tin-binated, spire short : outer volution much expanded laterally, 

 in adult specimens fully twice as broad as high, subangular above and 

 below and shouldered above, its basal portion concavely and oblitiuely 

 excavated around the narrow but deep central umbilical perforation. 

 Volutions apparently about three, though the apex is broken off in the 

 few specimens collecied, those of the spire rounded and ventricose : outer 

 volution truncated very obliquely backward at the aperture, broa.dly flat- 

 tened and somewhat concavely depressed above the shoulder, on the apical 

 side, but with a narrow, rounded and moderately ele\ated spiral promin- 

 ence next to the suture, — compressed laterally below the shoulder, on the 

 peripheral region, and broadly as well as concavely constricted just above 

 the basal angulation, which, in one specimen at least (figs. 2 and 2a) bears 

 a single series of large tubercles. 



Slit band placed at a short distance below, ur anterior to, the shoulder 

 of the outer volution. Surface marked with transverse but flexuous stria:" 

 of gi'owth which curve gently backward to the slit band. 



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

 1888 : one small specimen, thte original of figs. 2 and 2a, with a consider- 

 able portion of the test preserved. Dawson Bay, Lake Winnipegosis, — 

 on a small island a little to the north-west of Beardy Island (two charac- 

 teristic fragments), — at the mouth of Steep Rock River (one large cast 

 of the interior of the shell), — about two miles west of Salt Point (the 

 large cast represented by fig. 3 on Plate xli), — at the mouth of the Red 

 Deer River (two specimens), and at the first small point north of the Red 

 Deer (one fragment) : J. B. Tyrrell and D. B. Dowling, 1889. 



Not a vestige of the test is preserved on any of the specimens from 

 Dawson Bay. Both this and the preceding species would seem to belong 

 to that group of species of which J-'/Kin-otoniKria labrosa, Hall, is the type, 

 and which Lindstrijm, in his memoir " On the Silurian Gastropoda and 

 Pteropoda of Gothland," calls the Divisio V, Incisee. 



(S.) Pleurotomaria. (Sp. Undt.) 



Plate 42, tig. 1. 



A single cast of the interior of the shell of a reversed or sinistial 

 species of Pleurotomaria, which is represented in outline on Plate xlii., 

 was collected by Mr. Tyrrell or the present writer in 1888, at Pentamerus 

 Point, Lake Manitoba. Not a vestige of the test is preserved on this 

 specimen, so that its specific relations cannot be ascertained. The name 



