Type of the Genus Massospondylus. 111. 



parallels the conditions of the several fragments of the bone 

 in Massospondylus. 



The transverse width of the head of the bone is less than 

 4 inches in the largest specimen and more than 3 inches in 

 the smallest, and the transverse width at the notch below the 

 articular head is about 1| inch. The bone is about 1^ inch 

 thick proximally and the surface is divided into two portions, 

 one for articulation with the ilium, and the otiier is part of 

 the acetabulum. This acetabular portion is truncated poste- 

 riorly and compressed on the underside, as thougli it had 

 extended in an antero-posterior direction to meet the acetabular 

 part of the ischium. 



The middle portion of the shaft is twisted at an angle of 

 about 45° to the articular head, directing the expanded distal 

 plate of the bone inward. The inner margin is fractured. I 

 infer that the pubes approximated towards each other poste- 

 riorly, converging by the thin inner border, which thus became 

 posterior, and that the bones each had a nearly straight 

 though slightly concave border, which was anterior and 

 external. The middle portion of the shaft preserved is nearly 

 4 inches long and fully 2 inches wide to the fracture. The 

 distal portion of the pubis is about 5^ inches long, less than 

 2 inches wide proximaily, and 2^ inches wide distally, with 

 the distal extremity truncated and thickened. It has a carti- 

 laginous border ^ inch deep on the inner side, and has the 

 anterior extremity of the fragment directed a little outward. 

 Hence I conclude that the pelvic girdle was constructed upon 

 the same plan as in other Saurischia, in which the ischium 

 and pubis are flattened elongated bones. The form of the 

 pubis seems to be conclusive in indicating affinity with the 

 Triassic Saurischia of Europe. 



The Hind Limb. 



The hind limb is known from the femur^ tibia, metatarsus, 

 and phalanges ; its characters are in harmony with the indi- 

 cations of the pelvis. The femur, however, is more slender 

 than might have been expected, and rather conforms to the 

 type of Palceosaurus than that of Zanclodon, The tibia is 

 similar in its characters. 



The Femur. (Fig. 7.) 



The femur (fig. 7) was relatively short and strong. It is 

 known from the proximal end 360, the distal ends 361 and 362, 

 and the middle of a shaft which preserves much of the internal 

 lateral trochanter. The distal end shows the base of the 



