[lambe] 



A NEW SPECIES OF PLATYSOMUS 



19 



micular raised markings. The outer surface of some of the bones of 

 the head, seen in fragments or as impressions, have a similar sculpture 

 but slightly rougher with a greater development of the vermiculations. 



In the upper flank-scales (figured) the height is more than twice 

 the breadth. The flank-scales lower in the trunk are larger, but 

 proportionately narrower, the height in them being three times the 

 breadth 



The upper margin of the flank-scales is prolonged upward in 

 front by a prominent, inner, fusiform ridge which extends along the 

 slightly curved anterior border. The upper end of the anterior ridge 

 passes behind the lower end of the ridge of the scale immediately 

 above. The entire outline of any one flank-scale has not been observed 

 as all the scales are in place and consequently the lower end and 

 posterior margin of each scale are h : dden by the overlap (or more 

 properly the underlap as the scales are viewed from within). 



Upper flank-scales of Platysomus canadensis; 

 inner surface; natural size. 



The upper flank-scales present the appearance shewn in the ac- 

 companying text-figure. The upper projecting ridge-end, or peg, 



