WHITEAVES.J DEVONIAN FOSSILS OF MANTTOHA, H'l'C. •>•)! 



the second p;iir of glabellar funt)\v.s, aiul nearly opposite tlii^ anterior 

 termination of each eye. (Habeliar furrows in thi'ee pairs, each latei'al 

 and oblique ; the first pair straight and very short, the second curved 

 and longer than the first, the third longer than the second and 

 curving obliquely into the occii)ital furrow on each side, thus separating 

 a pair of lateral lobes at the base of the glabella. Occipital lobes repre- 

 .sented by a pair of small, distant tubercles in the occipital furrow, one 

 placed close to and innnediately behind the postero-lxisal angle of each of 

 the latero-basal lobes of the glabella : occipital furi-ow narrow occipital 

 ring rather broad and flat. Cheeks niodei'ately promijient ai'ound the eye- 

 lobe, sloping I'ather abruptly downward and outward : eyes prominent, 

 ajipressed close to the sides of the glabella, and placed much nearer to 

 the occipital fui'row than to the anterior or lateral margins of the 

 cejihalic shield. 



Thoracic segments, apparently nine in number, those of the axis 

 prominent and strongly convex, the pleura^ not quite so convex. 



Pygidium rather more narrowly rounded at its outer margin than th(.' 

 cephalic shield, its border narrow and flat- axis composed of fr(jm about 

 eleven to thirteen segments : pleurie about nine. 



Glabella and fixed cheeks nunutely tulierculated, the flat frontal area 

 smooth. Surface markings of thoi-ax and pygidium unknown, as the test 

 is not preserved upon either, in any of the specimens collected. Under a 

 lens, however, well preserved casts of the pygidium show that its axis 

 and pleura' are also minutely tuberculated, and that there is ,t compai'a 

 tively large pair of tubercles on each annulation of the axis, one on each 

 side of its outer boundary. 



Approximate length of the most perfect .specimen collected, as measured 

 in the median line, twenty-one millimetres ; greatest breadth of the 

 thorax of the same, ten millimetres. 



"Western Shore of Dawson Bay," Lake Winnipegosis, "from slabs 

 apparently derived from the neighbouring cliffs," J. \V. S))encer, 1874 : 

 one cast of the head, tninus the free cheeks, and casts (if two pygidia- 

 Several additional specunens of this trilobite were collected by Mr. 

 IJowling in 18<S8, and by Mr. Tyrrell in 18S9, in the Striiig(jcephalus 

 zone at three small islands in the southei-n portion <if Dawson Bay, and 

 at an exposure on tlie south-westei'n shore of that bay, about two miles 

 we.st of Salt Point. These specimens consist of a. few detached heads, 

 with the free cheeks in place, some with most of the test ]ii'eserved ; 

 numerous sharply defined casts of the jiygdium ; one cast of the doi-sal 

 surface of the united head (minus the fi'ee cheeks), thorax and pygidium ; 

 an united head and thorax, and a cast of the thorax and p\gidium. 

 December, 1892. 7 



