348 CONTRIBUTIONS TO CANADIAN PAL.EONTOLOOy. 



iSpecimeii No. 2, which not figured, was collected by Mr. Tyrrell or 

 the present wiiter, in 1888, at Monroe Point, Lake Manitoba. It is a 

 portion of a glabella of a rather lai-gei- individual than the last, with a 

 vei'v short pieci:' of the postero-uiedian spine preserved. It is very imper- 

 fect anterioi'ly and shows only two pairs of the lateral glaljellar depres- 

 sions. The tuberculation of the surface, however, is much more clearly 

 shcjwn in it than in specimen No. 1. 



Specimens Nos. 3 and 1. These are two examples, rjne of which is 

 figui'cd (Hg. 0), of the central porticjn of the head of still larger indivi- 

 duals than Nos. 1 and 2, collected by Mr, Tyrrell and the preseixt writer, in 

 188H, at Peiitamerus Point, Lake Manitoba. Both are nearly [jei'fect 

 anteriorly, but injperfect pjosteriorly. Tliey show that the front margin 

 of the head is nearly straight, or but slightly convex in the centre, and 

 that it is ))oi-dei'ed by a narrow i-aised rim, wliich is succeeded by a trans- 

 verse, linear depression or faint gi-oiA-c ( )n the glabella of Ijoth there are 

 three pairs of short lateral depi-es-ioris or pits. The jjostero-median spiue 

 of each is bi-oken off and scarcely a vestige reinaiiis in either of the two 

 postero-lateral spines. The tubei'culation cjf the suii'ace is well prespi'X'ed 

 in both, and in one of these specimens thei'c is ,i low conical tubercle, 

 much lai-ger than any of the others, nearly iu the centre of the glabella. 



Specimen No. "> (fig. 7). This is afi-agn]ent of the anterior portion of 

 the head of an individual of much larger size even than Nos. 3 and 1, col- 

 lected by Mr. I)<jwling, 188'J, on the west side of Dawson Bay, at the 

 south end of Itowa.n Island. The anteilor and median latei'al depi-es- 

 sions of the glabella are well shown on the right side of this speeinien, 

 and the posterior lateral depression on the li'ft. The surface of these de- 

 pressicjiis is nearly smooth and the more or less scattei'ed tubercles upon 

 the i-eiiiaindei- of the t(-'st are \cvy ii'r(^gula.i- in their distribution. When 

 exanjined with a lens, the anterior poi'tion of the glabella sIkjws traces of 

 laised lines running parallel to the front mai'gin of the head. 



The [)osition of the eye is not indieated in any of these specimens, and 

 not a vestige of the free cheeks is pivser\'ed. Still, the few fragmentaiy 

 examjiles so far obtained seem to indic.-it(! a hitherto undescribed species 

 of Jji-iiii/riis, in which the pOstero-median spine <if the glabella and the 

 pair of p(.)stei'(j-latei'al spines on the tix(;d cl]<'eks, ai'e far longer and more 

 slender than the coi-responding spines on the head of the ]>. rJihiurcros 

 of Jjari-ande.=!= Apart from the eirciimstance that they both beai- three 

 spines on the posterior portion of the head and, p(jssibly another in the 

 centi-e of the glabella, tliei'e is indeed very little resemblance betwe(.'n 

 this species and Ji. rliuioivros, t]\r shape and sui'face ornamentation of tin' 

 glaljella, and the modifications of the glabellar furr-ows in these two foi-ms 



*Sil. Syst. du Centre rlB la Bohemt, vol. [, Siippl., 1S72, p. 131, pi. ix, tig.s. 12-l!l. 



