The distal end of the humerus ends in a trochlea, with a larger knob for the ulna and a smaller oval knob for the radius.
When the wing is folded the long glenoid surface of the head of the humerus is bordered above by the tuberculum externum or superius, in the middle and below by the tuberculum medium or inferius for the insertion of the coraco-brachialis posterior muscle.
The hind-limbs are elongated, with four toes, of which the metatarsals are separate; the tibia and fibula are welded in old age; the calcaneum and astragalus of the tarsus are elongated; and there is a perforation on the inner side of the lower end of the humerus (see Jumping-Hare).
It is now possible to define the suborder Hyracoidea as including ungulates with a centrale in the carpus, plantigrade feet, in which the first and fifth toes are reduced in greater or less degree, and clavicles and a foramen in the lower end of the humerus are absent.
The humerus lacks a foramen at the lower end; and the molar teeth, as explained and illustrated in the article Vole, consist of two longitudinal rows of triangular alternating vertical prisms, and may be either rootless or rooted.
The vertebrae of the neck unite by nearly flat surfaces, the humerus has lost the foramen, or perforation, at the lower end, and the third trochanter to the femur may also be wanting.
The high cheek-bone and the hawk'sbill nose are universally distributed in the two Americas; so also are proportions between parts of the body, and the frequency of certain abnormalities of the skull, the hyoid bone, the humerus and the tibia.
On the outer side of the humerus between the head and the crista inferior is a groove lodging one of the coraco-humeral ligaments.
Two specimens of the humerus have been found in the English fens (Ibis, 1868, p. 363; Proc. Zool.
The humerus is stout and rather short.