THE MAMMA.LIA OF THE DEEP RIVER BEDS. 145 



arched forward and more slender in proportion to their length ; the distal carina? are 

 more prominent and more extended upon the anterior face of the trochlea. 



The phalanges (PI. V, Fig. 42) of the pes are like those of the manus, except 

 for their greater size, and the curious, trowel-shaped unguals have their peculiarities 

 somewhat emphasized. 



Measurements. 



M. 



Diameter of acetabulum, fore and aft 029 



Diameter of acetabulum, vertical • • • -028 



Width of pelvic opening at pubes T 059 



Femur, length 190 



Femur, width of proximal end .' 050 



Femur, diameter of head, fore and aft 025 



Tibia, length 177 



Tibia, breadth of proximal end 044 



Tibia, breadth of distal end 028 



Astragalus, length 035 



Astragalus, width of proximal trochlea 020 



Calcaneum, length 064 



Cuboid, height 020 



Metatarsal iv, length 075 



Metatarsal iv, width of proximal end 013 



First phalanx of third digit, length 022 



First phalanx of third digit, width of proximal end 013 



Second phalanx of third digit, length 012 



Third phalanx of third digit, length 016 



Third phalanx of third digit, width of proximal end 013 



Mesokeodost intermedius Scott. 



Amer. Naturalist, 1893, p. 661 . 



This species is represented by foot-bones belonging to two different individuals, 

 which are so different in their proportions from those of the foregoing, species that 

 they must be referred to another animal. The only skull which can with any proba- 

 bility be regarded as belonging to M. intermedins is a small one belonging to a very 

 immature individual and therefore of little value for systematic purposes. The milk 

 teeth are still in place, the permanent canines just beginning to appear, and the first 

 permanent upper molar already protruded. This latter tooth is somewhat like that 

 of Merycliyus in the shape of the external crescents and in the rapid narrowing of 

 the valleys towards the base of the crown. The inner crescents, however, are not 

 like those of the Loup Fork type. 



One of the typical specimens (PI. V, Fig. 43) consists of the third metacarpal 

 entire and the proximal three-quarters of the fourth. As compared with those of 



