NO. 5 UI'PER CAMBRIAN TRILOBITES RESSER 67 



a third longer than wide, and has several pairs of glahellar furrows. 

 The brim is narrower than the neck ring, a characteristic common to 

 several of the Canadian species. The brim joins the eye ridges, which 

 also form a raised band. The rather large eyes are situated well 

 forward. The fixigenes, less than half the glabellar width, contract 

 forward to meet the relatively narrow brim. 



A beautiful pygidium with a wide flaring border bears two spines 

 on each side. Its short, wide axis extends into a long postaxial ridge. 

 Only two axial rings and pleura are defined. The entire pygidium is 

 covered by prominent anastomosing lines. 



Lyell formation; (loc. 6j\.i) Mons Glacier, 50 miles northwest of 

 Lake Louise, Alberta. 



Holotype. — U.S.N.M. No. 108752a; paratype. No. 108752b. 



ELLIPSOCEPHALOIDES DECLIVIS, new species 



Plate 12, Figures 10-13 



This species is represented by several cranidia. It is similar to 

 E. mono us is except for the more posterior position of the eyes. The 

 long, parallel-sided glabella is rounded in front, and in cross section 

 stands completely above the palpebral lobe. The rear pair of glabellar 

 furrows is continuous across the glabella and one shallow pair is 

 visible anterior to it. The fixigenes, measuring less than half the 

 glabellar width, slope down steeply from the dorsal furrow, though 

 at a lesser angle than the sides of the glabella. The eyes are of normal 

 size and are connected by a thickened eye ridge with the narrow 

 convex brim. 



Lyell formation; (loc. 20j) Tilted Mountain Brook, 9^ miles east 

 of Lake Louise, Alberta. 



Holotype. — L^.S.N.M. No. 108754a; paratype. No. 108754b. 



MARY VILLI A Walcott, 19 16 



MARYVILLIA WYOMINGENSIS (Resser) 



Plate 12, Figures 14-20; Pl.a.te 14, Figure i 



Bathyuriscus sp., Walcott, U. S. Geol. Surv. Monogr. 32, p. 466, pi. 64, fig. 6, 



1899. 

 Coosia wyombujciisis Resser, Smithsonian Misc. Coll., vol. 95, No. 22, p. 7, 



1937- 



Heads and tails of a species of Maryvillia occur throughout the 

 Yellowstone Park region ranging from Clark Fork, Wyoming, to the 

 Castle Mountains, Montana. A good cranidium on the hand specimen 

 with the holotype of Tricrepicephalus tripunctatus (\\^hitfield) comes 

 from Moss Agate Springs in the Castle Mountains, Montana. 



