336 



Annals of the Carxegik Muskam. 



Fk;. I. ( )utline draw- 

 ing of the type specimen 

 of Bathyiirus aiigeliiii 

 Billings to show its dis- 

 torted condition. \ nat. 

 size. 



Canada, and, so far as is known, it does not occur outside of the Ottawa 



Valley. Through the courtesy of Professor Joseph F. Whiteaves of 

 the Dominion Survey, the writer has been 

 enabled to study three specimens, including 

 the type, and, in order to make this list of 

 Chazy trilobites complete, figures of them are 

 inserted here. The type specimen is in a bit 

 of sandy shale, and is very much flattened 

 and somewhat distorted by pressure. (See 

 figure I.) The other two specimens, a crani- 

 dium and a pygidium, are in the characteris- 

 tic upper Chazy limestone of the Ottawa Val- 

 ley and are accompanied by great numbers of 

 Ostracoda. They are both on weathered sur- 

 faces and retain their normal convexity. The 



above line drawing is from the type sj^ecimen and the others are 



figured on plate lo. 



Description. 



Cephalon wide, moderately convex, the free cheeks extended back 

 into sharp spines ; glabella subcylindrical, extending almost to the front 

 border, from which it is separated by a narrow groove. Two pairs of 

 oblique glabellar furrows are faintly visible in the proper light. The 

 first pair have their anterior ends just at the front of the eyes and their 

 course isoblitjuely backward. The second pair originate opposite the 

 middle of the eye lobes, run about parallel to the first pair, reaching 

 nearly to the neck furrow. Eyes very large, close to the glabella, and 

 reaching the neck furrow posteriorly. Free cheeks large, the suture 

 running from the eye straight forward to the margin, close to the 

 glabella. A narrow, striate, upturned border extends all around the 

 front and sides of the cephalon. 



Thorax. — The number of segments cannot be determined. The 

 type specimen shows eight, but they are so pressed out of position that 

 the thorax is much shorter than it should be and appears to taper too 

 rapidly. Axis less than one third the width, strongly convex. Seg- 

 ments on the pleura are obli(|uely grooved. 



Pygidiimi strongly convex, semicircular, with a narrow, depressed 

 border. Axis very convex, smooth, but shows three or four pits at the 

 sides near the anterior end. Instead of being abruptly terminated be- 

 hind, as in Batliyunis extans Hall of the Black River limestone, the axis 



