Maryland Geological Survey 205 



from the outer (calcaneal) side is somewhat exaggerated, and gives it a 



superficial resemblance to the strong upward process of the astragalus of 



Creosaurus. The calcaneal facet is of much greater extent than in 



D. alius, the posterior margin being nearly straight in the present species, 



whereas in D. alius it is sharply curved. The bone under consideration 



is of less fore and aft diameter than that of D. alius, while its transverse 



diameter is nearly half again as great. This is in part doubtless due to 



the worn condition of the present type. 



The dimensions of the astragalus are as follows : 



Transverse diameter 78.0 mm. 



Greatest fore and aft diameter 50.5 mm. 



Least fore and aft diameter 26.0 mm. 



Height 56.0 mm. 



Metatarsal ii (pi. xix, fig. 7, left) differs from that of D. latus by its 

 larger size, the greater roundness of the articular face, indicating a some- 

 what more mobile Joint, and in the lesser prominence of the outer keel. 

 The depressions upon the lateral faces of both metatarsals are much more 

 pronounced than in D. alius. Width of the articular extremity, 34 mm. ; 

 fore and aft diameter, 33.5mm. The bone is extremely hollow; the 

 maximum thickness of the walls of the shaft being 4 mm. The mediiUary 

 cavity extends well down into the articulation. 



Metatarsal iii (pi. xix, fig. 7, right) is also represented by its distal 

 articulation and a small portion of the shaft. It in turn differs from that 

 of D. alius in having no median fore and aft depression over its articular 

 face, except a very slight one in front. Its dimensions are as follows : 



Widtli of the articular extremity 43.5 mm. 



Fore and aft diameter 33.7 mm. 



Width of shaft at fracture 50 mm. above end 29.0 mm. 



In this bone the walls are somewhat stouter, measuring 6 mm. as a 

 maximum. 



The proximal phalanx of digit iii (No. 5703) is unfortunately from a 

 much smaller individual but differs from, that in D. alius in having no 

 trace of a median antero-posterior ridge in correspondence wiih. the 

 lack of an equivalent groove in the articulation of the metatarsal. The 



