22 



Lai'ger dermal scute : — 



Length 20 



Breadth 14 



Maximum height or thickness 7 ' 5 



Average diameter of pits 3 



Tooth :— 



Length l 1 7 ' 5 



Antero-posterior diameter at base 9 ' 2 



The above crocodilian remains are referred provisionally to the species lately described 

 by Dr. F. B. Loomis, from the Titanothere beds of South Dakota. The larger vertebra from 

 the Cypress hills agrees well in size, and general proportions with the South Dakota dorsal 

 centrum (p. 428, fig. 3, of Dr. Loomis's paper), whilst the larger dermal scute closely 

 resembles the Dakota plates in the disposition and size of the surface pits 



MAMMALIA. 



MARSTJPIALIA. 



DlDELPHTS VALENS, Sp. UOV. 



Plate VIII, figs. 1-7. 



An upper right molar from Bone coulee, Cypress hills, is provisionally referred to this 

 genus. The tooth in crown view, is triangular in outline, has three prominent V-shaped 

 cusps, and a strong external style-bearing cingulum. Of the three cusps, the internal 

 one (protocone) occupies the apex of the triangle, the other two (paracone and 

 metacone) form an antero-posterior pair somewhat removed from the external face of 

 the tooth by the strong development of the cingulum. The three primary cusps are 

 compressed anteroposteriorly, the protocone to a less extent than the other two; all have 

 their external slopes well excavated. The protocone is the stoutest, and is of about the same 

 height as the paracone, which is the smallest ; the metacone is conspicuously higher than the 

 others. At the base of the posterior spur of the protocone, is a decided though small fourth 

 cusp that may represent the hypocone. Three principal stylar cusps occur in the cingulum. 

 Of these, the most prominent occupies a position only slightly posterior to the mid-length 

 of the cingulum : it is compressed transversely, and has a vertical external face with a some- 

 what rounded iuternal slope ; its height is nearly equal to that of the paracone. Of the other 

 two stylar cusps one is at either end of the cingulum, the anterior one being the larger of the 

 two. The demarcation between the anterior style and the large one posterior to it is very 

 decided, and is accentuated by a furrow in the vertical external face of the cingulum. On 

 the anterior slope of the central stylar cusp are two inconspicuous secondary styles. The 

 cingulum is continued round the anterior base of the paracone as a narrow shelf. The crown 

 is borne on three short roots. 



This tooth, plate VIII, figures 1-4, probably the second or third upper molar, is consider, 

 ably larger than (slightly more than one-third as large again as) the corresponding molars 

 of Didelphys (Peratherium) fugax, which exceeds in size the other species of the genus 

 described by Cope from the Oligocene of Colorado. For the species represented by the 

 Cypress Hills tooth the name valens is proposed. Collection of 1904. 



