NO. 3 CAMBRIAN TRILOBITES 223 



Micromitra (Patcrina) wapta Walcott. 



Obolus parvus Walcott. 



Acrothele colleni Walcott. 



Wimanella simplex Walcott. 



Hyolithellus. 



Hyolithes. 



Alhertella bosworthi Walcott. 



Albertdla helena Walcott. 



Bathyuriscus. 



Agraulos stator Walcott. 



Ptychoparia. 



Formation and locality. — ^Lower Cambrian: (35c) Drift blocks of 

 siliceous shale supposed to have come from the Mount Whyte forma- 

 tion, found on the south slope of Mount Bosworth, about 500 feet 

 (152 m.) northwest of the Canadian Pacific Railway track between 

 Stephen and Hector, eastern British Columbia, Canada. 



Genus KARLIA Walcott 



Karlia Walcott, 1889, Proc. U. S. Nat. Mus., Vol. 11, p. 444. (Described 

 as below.) 



Form elongate-oval, convex. Head longitudinally semicircular, 

 deeply marked by the dorsal furrows. Glabella clavate, broadly 

 expanded in front, with or without faint glabellar furrows. Occipi- 

 tal furrow well defined. Fixed cheeks subtriangular ; posterior 

 furrow broad : eye lobe small ; free cheeks narrow. Hypostoma 

 with a thick, rounded anterior margin that is produced into the large 

 lateral wings, the sides of which extend one-half way back on the 

 oval, convex body; posterior marginal rim strong and separated 

 from the body by a well-defined sulcus. 



Thorax with seven segments ; axis with a central spine on each 

 segment ; pleural lobes with a broad groove ; anterior lateral ends 

 of pleurae faceted. 



Pygidium short, transverse, four to five segments in the axis, 

 lateral lobes slightly grooved. 



Surface granulose. 



Genotype. — Karlia minor Walcott. 



Stratigraphic range. — ^Middle Cambrian. 



Geographic distribution. — Eastern Newfoundland ; Canadian 

 Rocky Mountains, British Columbia, Canada. 



Observations. — The compact, strong dorsal shield of Karlia at 

 once recalls that, of Bathyuriscus. It dififers from the latter in its 

 small eye lobes, and seven instead of 10 or 11 thoracic segments. 



Two species only have thus far been referred to the genus. 



