1913] 



The Ottawa Naturalist. 



59 



directions and has a maximum breadth behind of 102 mm., 

 with a length, measured from its sutural junction with the pygal 

 to the centre of its front margin, of 84 mm. The second 

 suprapygal is diamond shaped, slightly longer than broad, 

 and more pointed in front than behind. 

 pygal is longitudinally and transversely 

 front than behind, with a length slight!} 



The surface of the 



convex, broader in 



exceeding: the front 



breadth; its dimensions are anterior breadth 62 mm., posterior 

 breadth 47 mm., length 70 mm. 



The second, fourth, sixth and eighth costal bones are greatlv 

 expanded di stall v, with a resultant decrease in the distal breadth 

 of the third, fifth and seventh costals. The proximal end of the 

 second costal abuts against the first and second neurals, and the 

 third is in contact with the second, third and fourth neurals. 

 The proximal ends of the seventh and eighth costal bones came 

 within the area of injury, which has resulted in the loss of the 

 eighth neural and the posterior half of the seventh, and are 

 missing. 



The first and third vertebral scutes are about as broad as 

 long. The sulcus marking the back border of the third curves 

 sharply forward in the centre whilst crossing the fifth neural. 

 The second and fourth vertebral scutes are slightly longer than 

 broad. The fifth vertebral is greatly expanded behind and its 

 lateral sulcus passes down the midlength of the tenth peripheral 

 bone. The nuchal scute is 34 mm. long and 26 mm. broad. 

 The supracaudal scute is 145 mm. broad behind at the free border 

 of the shell, and 73 mm. long in its middle line, its anterior 

 sulcus crossing the second suprapygal 15 mm. in advance of the 

 centre of the latter's posterior margin. The dimensions of the 

 neural and costal bones and vertebral scutes are given in mm. in 

 the following table : 



