310 THE OSTEOLOGY OF ELOTHERIUM. 



VIII. The Hind Limb. 



The pelvis is remarkable in man)' ways. As a whole, it is curiously long and 

 narrow, except anteriorly, where the sudden and strong eversion of both ilia gives it con- 

 siderable breadth. The ilium is elongate, and has a long, heavy, trihedral peduncle, 

 which expands quite abruptly into the broad anterior plate. This plate is very strongly 

 everted in its anteroinferior portion, and in shape is not at all like that of Sus, or of most 

 existing artiodactyls, but rather resembles that of such ancient perissodactyls as 

 Palceosyops. The plate rises high above the sacrum and conceals much of that bone from 

 view, when the pelvis is seen from the side ; the gluteal surface is concave and the sacral 

 surface strongly convex ; the suprailiac border is quite thin for most of its course, but 

 becomes very thick and rugose at its inferior angle. The iliac surface is relatively wide 

 and may be traced through the whole length of the bone, the pubic border being very 

 distinctly marked throughout. The ischial border is, for the most part, thick and 

 rounded, but becomes -harp and compressed above the acetabulum. The pectineal process 

 is a very prominent and rough tuberosity, and a second rugosity lies above and behind 

 it. Tlie acetabulum is rather small, but deep, and is of almost circular form ; its 

 articular surface is but little reduced by the deep ami narrow sulcus for the round 

 ligament. 



The ischium is likewise elongate, though much shorter than the ilium; above the 

 acetabulum its dorsal border arches upward into a high, thin and roughened crest, the 

 ischial spine, very much like that -ecu in Sus, behind which is a distinct ischiadic notch, 

 a difference from the true pigs, which have no such notch. For most of its length, the 

 ischium is laterally compressed, but expands posteriorly into a large, thick plate, with 

 everted hinder binder and very massive tuberosity. The pubis is short, heavy and 

 depressed. The symphysis, in which both the pubes and the ischia take part, is very 

 long, the posterior notch between the two ischia being shallow. Consequently, the 

 obturator foramen is much elongated antero-posteriorly, and of oval shape. This region 

 of the pelvis is entirely different from that of Sus, in which tin- ischia are widely 

 separated behind, the symphysis is short, and the obturator foramen is nearly circular in 

 outline. In Hippopotamus the pelvis is more like that of Elotherium, but is much larger 

 and more massive in every way: the peduncle of the ilium is not so elongate or so 

 slender, the spine of the ischium is very much less prominent, and the posterior expansion 

 of the ischium i> very much larger and heavier. Unfortunately, the pelvis is not 

 sufficiently well known in Ancodus or Anthracoihermm for comparison with that of 

 Elotlu num. 



The femur is a long and proportionately rather slender bone. The proximal end is 



