36 ROYAL SOCIETY OF CANADA 



five rings, of which the first bears a short spine, the next three have 

 tubert-les, and tlie last which is mutilate, contains two somites. 



Sculpture.— The surface where visible is seen to be covered with small 

 tubercles, arranged on the cheeks in irregular rows more or less trans- 

 verse. On the area in front of the ocular ridge they arc diversified with 

 rai.<ed lines parallel to the front border. 



Size. — Length of the cephalic shield 35 mm., width of the middle- 

 piece opposite the fourth furrow 40 mm. ; at the eye lobes 42 mm. ; at 

 the genal angle about 60 mm. I make the following estimate of si/e 

 from a half grown individual ; whole length of the test exclusive of spines 

 75 mm. ; width at the genal angles 60 mm ; width of thorax, exclusive 

 of spines 45 mm. Length of head-shield oO mm. ; of thoi-ax 27 mm. ; of 

 jiygidium exclusive of the spines 2M mm. 



This fine species is comparatively rare at Mount Stephen. It is 

 distinguishable from ]V. serratus by the wider glabella, the lower and 

 more even ocular ridge and by the ornamentation of the surface ; it also 

 grows to a larger size and has shorter spines to the movable cheeks, pleurœ 

 and i)ygidium. 



The species has more the aspect of a Dorypj-ge than the preceding 

 one, but it differs from that genus in having only five pairs of spines on 

 the p3^gidium as well as in the strong angulation of the pleurœ and 

 pygideal spines, and in having furrows on the glabella. 



DOKYPYGE, Dames. 

 DoRYPYGE Dawsoni, Walcott sp. (PI. III., fig. 1.) 



Bathyurus ? Roeni., Acad. Nat. Sci. Phil., Proc, pt. 1, '87, p. 18, pi. i, fig. 8. 

 Bathyuriscxis (Kootenia) dairsoni n. sp., Wale, U.S. Nat. Mus. Proc, '88, p. 446. 

 Karlia Step?ienensis Wale. ? Proc. U.S. Nat. Mu.s., 1888, p. 44.5. 



Tliis species was very inadequately described by Dr. Roemingcr. Mr. 

 Walcott has described it more fullj-, but examples in the collection 

 received from Mr. Walker show that its characters are not yet fully 

 understood. 



It is somewhat remarkable that the spines of the pygidium, which, 

 with the characters of the head-shield, refer it to Dorypyge should not 

 have been ob.served by either of the above authors, but they are slender 

 and might be obscure in poorly preserved tests. As Mr. Walcott's 

 description (which, however, is not accompanied by a figure) has been 

 J)ubli,^hed in the Proceedings of the United States Natural Museum, it 

 seems not necessary to reproduce it here. Hut of the glabella it may be 

 said that it is wider in front than behind. Also that there are slender 

 terminal spines to the four posterior pairs of pleurœ. Also that the 

 rachis of the ])ygidium is separated from the posteiior border hy ix narrow 

 area ; al.so that the rachis has six rings ol" which the posterior has no 



