0. C. Marsh—American Jurassic Dinosaurs. 169 
shallow (Plate VII, figure 1, ac.) The face for union with the 
ischium is large and rugose, but that for the pubis is much less 
distinct. The post-acetabular part of the ilium is very short, 
scarcely one-third as long as the anterior projection. 
e ischium of Stegosaurus ungulatus was figured and de- 
scribed in the communication already cited. It is short and 
robust, and has a prominent elevation on the upper margin of 
the shaft (Plate VIII, figure 2). Its larger articular face meets 
a post-acetabular process of the ilium, and a smaller articula- 
tion joins the pubis. The shaft of the ischium is twisted so 
that it resembles somewhat the corresponding bone of Moro- 
saurus, 
_ The pubic element of the pelvis of Stegosaurus ungulatus is 
in general form somewhat like that of Camptonotus. The true 
pubis consists of a strong spatulate process, projecting forward 
nearly horizontally. (Plate VIII, figure 2, p.) Its proximal end 
articulates with the pre-acetabular process of the ilium. The 
post-pubie branch extends backward and downward, nearly to 
the end of the ischium. The two bones fit closely together 
in this region. The usual pubic foramen is in this species 
replaced by a notch, opening into the acetabular cavity. In a 
smaller undescribed species, which may be called Stegosaurus 
afjinis, the post-pubic bone is slender and more rod-like, not 
flattened, as in the specimen here figured. 
Tue Hinp Limp. 
The large bones of the leg of Stegosaurus ungulatus have 
already been figured, and their main characters described. The 
emur is remarkably long, and without a third trochanter. The 
tibia, on the other hand, is very short. When the animal stood 
at rest, these two bones of the leg were nearly in the same line, 
as shown in Plate VIII, figure 2. The fibula is slender, and 
has its larger end below. 
he astragalus is firmly codssified with the tibia, and the 
caleaneum is also united, but less securely. ere are three 
bones in the distal row of tarsals. (Plate VIII, figure 2.) The 
one on the inner side is massive, and semi-circular in transverse 
outline. The median tarsal is still larger, while the outer one 
'S quite small. There are five well developed metatarsais, 
which are of moderate length, and robust proportions. The 
first digit is terminated by a strong, broad, ungual phalanx, 
the largest of the series. The second, third and fourth digits 
also have similar phalanges of smaller size. The outer digit 
has “ee a tubercle at itsextremity. The number of phalanges 
In the fourth and fifth digits has not been exactly determined, 
but they were less than the usual number. 
