3l6 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 53 



OLENELLUS CANADENSIS, new species 



Plate 38, Figs, i-io 



Olenellus canadensis Walcott (in part), 1908, Canadian Alpine Journal, 

 Vol. I, No. 2, p. 242. (Name used in list of fossils occurring in geologic 

 section. The specimens listed include forms now referred to Olenellus 

 gilberti.) 



Olenellus canadensis Walcott (in part), 1908, Smithsonian Misc. Coll., 

 Vol. 53, No. 5, p. 215. (Name used in section. In both cases, however, 

 the specimens listed include forms now referred to Olenellus gilberti.) 



Cephalon semicircular in outline, convex ; bordered in large speci- 

 mens by a strong, moderately convex outer marginal rim that is 

 narrow in front of the glabella, and that gradually broadens out on 

 each side toward the genal angle, where it is continued as a long, 

 strong, rounded spine. The posterior marginal border is narrow, 

 slightly rounded, and merged at the genal angle into the outer border ; 

 in some large specimens the genal angle is carried forward and an 

 intergenal angle [fig. i] occurs about three-fifths of the distance out 

 from the glabella to the outer margin of the cephalon ; in other speci- 

 mens the posterior border extends without interruption from the 

 glabella out to the genal spine, as shown by fig. 4. Glabella elongate, 

 occupying the entire length of the cephalon between the anterior, 

 rounded border and the occipital ring; the anterior lobe is nearly 

 as long as the three posterior lobes, transversely elliptical in outline, 

 somewhat tumid, and nearly one-third broader than the posterior 

 lobe : the two lobes next back of the anterior lobe are united at their 

 outer ends, the furrow between them not extending to the dorsal 

 furrow ; the posterior lobe is transverse, arching slightly forward 

 at the ends, and about the same width as the occipital ring and the 

 two lobes in front of it ; on some of the more perfectly preserved 

 cephalons there is a slight median node at the posterior margin of 

 the two posterior glabellar lobes and the occipital ring [see fig. 6]. 

 Occipital segment broad, slightly convex, and in appearance similar 

 to the posterior lobe of the glabella. 



Eye lobe short, crescentiform, narrow, extending from the base 

 of the expanded anterior lobe of the glabella backward and opposite 

 the two anterior, narrow lobes ; the posterior end of the eye lobe is 

 separated from the dorsal furrow beside the glabella by a narrow, 

 elongate subtriangular tubercle that extends from opposite the second 

 narrow glabellar lobe back nearly to the rounded posterior marginal 

 rim of the head. Cheeks broad, moderately convex, and marked 



