WHiTEAVEsJ DEVONIAN FOSSILS OF MANITOBA, ETO. 307 



mould of the exterior, but the ventral margin is slightly restored from 

 the lines of growth. The shell seems to have been larger and more glo- 

 bose than P. ellipfu-a, but the wax impression from which the figures were 

 made does not give a clear idea of the shape of the valves, or of their 

 surface markings. 



(S.) CoNOCARDiuM Ohioense, Meek. 



Coiioranliiim Ohioen.se, Meek. 1871. Proc. Ac. Niit. Sc. Philad., p. 9. 



Meek. 1873. Geol. Surv. Ohio, vol. I, pt. 2, p. 2(«, pi. .vviii, 



tig. 9, and wood-cut a on p. 204. 

 Hall. 1883, Pal. St. N. York, vol. V, pt. 1, Plates and Expl., 



pi. Ixviii, figs. 2 and 3. 

 Hall. 1885. Pal. St. N. York, vol. V, pt. 1, Lamellil)r., 2, p. 



411, pi. Ixviii, figs. 2 and 3. 



" Western shore of Dawson Bay," Lake Winnipegosis, "from slabs ap- 

 parently derived from the neighbouring cliffs," J. W. Spencer, 1874 : four 

 specimens. 



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

 188S ; four specimens. Dawson Bay, at Whiteaves Point, and about two 

 miles west of Salt Point, J. B. Tyrrell, 1889 : one specimen from each of 

 these localities. 



Most of the specimens obtained at these localities are small and oVjvi- 

 ously immature, but a single and nearly perfect specimen, collected by Dr. 

 iSpencer, is fourteen millimetres in length and nine millimetres in height. 

 In this individual "the body of the shell," as stated by Hall, in his de- 

 scription of C. Ohioensi^, " is marked by about six strong radiating plica- 

 tions on the ventricose portion of the valve, and on each side by more 

 numerous and smaller plications. The interspaces between the ribs are 

 marked by lamellose concentric stria?." 



Some palaeontologists are of the opinion that C. Oliioeniti' is only the 

 young of the C. tvvjtniale of Hall, which Professor Hall now regards as a 

 synonym of C. cuneus, Conrad. 



(S.) Cardiopsis tenuicostata. (N. Sp.) 



Plate 40, figs. 1 and 2. 



Shell of medium size, moderately convex, subcircular or ovately subcir- 

 cular, inequilateral and a little longer than high. Umbones prominent, 

 beaks incurved, inclined forward and placed in advance of the midlength ; 

 superior border nearly straight but slightly concave in the centre, behind 

 the beaks ; ligamental area narrowly lanceolate in outline, as viewed from 

 above. 



