120 



PROCEEDINGS OF THE NATIONAL MUSEUM. 



VOL. 56. 



Type locality. — South Branch of Sand Creek, Province of Alberta, 

 Canada. 



Horizon. — Belly River formation ("200 feet below the top"), 

 Upper Cretaceous. 



The characters which distinguish Boremys alhertensis from B. 

 pulchra Lambe may be summarized as follows: Larger size (nearly 

 one-third); additional supramarginal scute separating first costal 

 from marginals; supramarginals wider than long; diameter of costal 





Fig. 3.— Carapace of Boremys Albertensis, new species. Type No. 8803, U.8.N.M. N. l, 2, S, 4, 



6, 6, 7, NEURAL BONES ONE TO SEVEN; nu., NUCHAL; pn., PRENEUBAL; pp., PYGAL; «. C. S., SUPERNU- 

 MERARY COSTAL SCUTES; S. TO. S., SUPRAMARGINAL SCUTES; Spy., SUPRAPYGAL. ABOUT TWO-FIFTHS 

 NATURAL SIZE. RESTORED.1 



scutes reduced transversely, median scute longer than wide; first 

 vertebral elongated; carapace more pointed, not broadly rounded in 

 front, first neural greatly elongated; inframarginals wdder than long; 

 intergulars overlapping entoplastron. 



Except for the parts that are missing the carapace is well preserved. 

 All the sutures between the bones and the scutes can be clearly 

 made out. 



I The posterior end of carapace restored from Boremys pulchra Lambe; see fig. 14., Trans. Royal Soc. of 

 Canada, vol 8, 1914, pp. 13-16. 



