Vol. 56.] DICKANOZYGOMA LEPTOSCELUS. 655 



The Hind-Limb. 



The femur lies with its head just below the pelvic acetabulum, 

 exposing the flattened superior or anterior surface. The bone is 

 4 inches long, more than 2 inches wide over the proximal end, with 

 the shaft constricted to less than | inch in width below the middle 

 of its length, and then widening distally to about 1 inch at the 

 distal articulation. The expanded proximal end is flattened or 

 slightly concave from post-mortem pressure, with the superior thin 

 proximal edge convex from within outward as in Cynognaihus, 

 and to a less degree in Tribolodon. But, unlike both these 

 Cynodont genera, the genus now described has no upward reflexion 

 of the trochanter major at the external margin, which is simply the 

 flattened outer extension of the bone; a condition to which the 

 Russian Deuterosauria and German Protorosauria approximate, 

 though in the latter type of Theriodontia the transverse expansion 

 of the head of the femur is small, and the proximal contour is not 

 transversely convex. 



The proximal articulation in this genus is well rounded on the 

 inner side of the head, where it is elevated to a distinct convexity 

 on the margin of the inner lateral aspect, as though the bone were 

 carried by the animal more or less horizontally. The proximal 

 edge of the bone on its terminal surface appears to have been 

 slightly convex from side to side, and it recedes from the articular 

 head as it extends outward. The length of the bone on the 

 external side is only 3 inches. The external lateral contour of 

 the femur is necessarily concave. The inner lateral contour is not 

 completely exposed, so that the width of the distal end of the bone 

 cannot be given exactly. It has been crushed, and although § inch 

 thick as preserved, it may have been a little thicker. The distal 

 articulation as preserved is not well rounded, and appears to be 

 less rounded than in some of the smaller types like Herpetocheirus 

 and Tribolodon, but not more than half of the condylar surface 

 is exposed: this has a vertical border on the external margin, 

 rounded at the angles. 



The tibia and fibula are in near contact with the distal end of 

 the femur. The tibia only shows 1| inches of its proximal end ; 

 and this is obscured by fracture, which has left enough of the 

 bone-tissue to mask the external form and character in the relief- 

 cast of the bone. As exposed, the truncated proximal end of the 

 tibia is | inch wide, and apparently but little wider than the fibula, 

 which appears to articulate with its proximal end by a small sur- 

 face on the inner side, where the two bones are in contact. 



The fibula as exposed is 3| inches long, but the distal end is 

 partly covered with matrix, so that, although its entire length 

 appears to be shown, it may have been a little longer. The 

 proximal end appears to be convex, and is obliquely truncated like 

 the proximal end of the ulna of a crocodile. It is | inch wide, and 

 defined by a sharp edge at the articular margin. The internal 

 longitudinal contour of the bone is concave, and the external border 

 nearly straight to the lower third of its length, where the shaft 



