.iril^ CONTRIBUTIONS TO CANADIAN PAL^ONTOLOCY. 



xVt the time that the introductiuii to this paper was written, the writer 

 was under the impression that the three specimens of the trilobite now 

 undei- consideration, collected by Dr. Spencer, represented "a variety of 

 I'riM-hi.K Hnldemani," as stated on payc '257 (lines 17 and 18 from the top). 

 A sul)sequent study of the whole of the specimens collected, however, 

 has led to the conclusion that they indicate a pii-viously undescribed and 

 ]ii'obably distinct species of Proi-fnn, which is more nearly lelated to the 

 /' Eo/i'i, Green (8p.), /' /-"rovt//., 8huniard, and P.cii rriinarffiiintn.SjIlsll, 

 as described and figured in the seventh volume of the Palicontology of 

 the State of New York, than to /' JJiihlenumi. The charactei-s by 

 which these three most nearly related species of I'njrlii.x can most readily 

 lie distinguished fi'om /''. iniiiidvjva, are as follows. The anterior margin 

 of the cephalic shield of 1'- Hoivi is not narrowly upturned, its eyes are 

 .apparently lai-ger proportionately than those of /' hhiikIhIuh, and theic 

 are only from nine to ten annulations in the axis of the pygidium of 

 /' Ri>iri, and from six to seven pleuite. J'. I'ron.fi has an upturned 

 border to the anterior njargin of the; head, but it is said to have four 

 pairs of lateral furrows on the glabella, eight to ten annulations on 

 the pygidium and six to eight pleurie. I' i-nrvuiKU-i/ii/ii/nN is described 

 as having four pairs of lateral glaliellar furiows, large occijiital loljes, 

 and a pygidium with thii-teen to fourteen annulations on the axis and 

 twelve pleura'. 



Two fragmentary spechjiens of a small trilobite which may be referable 

 to P. iii.n.'iuhiJ ii.s, were collected by Mi-. Tyrrell in 1889, at Devils Point, 

 Lake Winnipegosis, from beds whose stratigraphical po.sition is imme- 

 diately below the Btringficephalus zone. These .specimens are mere casts 

 of the under surface of the right free cheek of two individuals. 



A few specimens, which are also probably referable to P. m.^iiididiis-, 

 were collected by Mr. Tyrrell, in 1889, from beds whose sti-atigiaphical 

 position is al)ove the Striiigocephalus zone, on the south-western shores of 

 Pelican and Cameron bays. Lake Winnipegosis ; in Dawson Bay, at the 

 lirst small jsoint north of the mouth of Bell River ; and on the Red Deei' 

 Kivei', at the Upper iSalt Spring. Most of the specimens fi-om these 

 localities are separate pygidia, with the test preserved. S(jme of these 

 [lygidia are much largei- and more narrowdy idunded posteriorly than 

 those of the typical form of /•■- immiluhm fi-om the Stringoce]ihalus zone, 

 and, in the largest of these large pygidia theie apjiear to be about thii'teen 

 or fourteen annulations on the axis and perhaps as many as eleven 

 pleune. The surface of these testiferous pygidia, also, when examined 

 with <i lens, is seen to Vje faintly and very minutely trdierculated. One 

 of the specimens from Camei-on Bay is it detached left free cheek with 

 the test preserved, but its lowei- surface only is exjiosed, the upper lieing 

 buried in the matrix. In this spr;cimen only the rather broad basal 

 portion of the genal spine is preserved. 



