TUBULIDENTATA To the order Tubulidentata belongs the aard-vark (q.v.) or African ant-bear, Orycteropus, representing the family Oryctero podidae, which was formerly associated with the American eden tates and the scaly ant-eaters because, feeding on termites, it has a longish snout, a long, extensile tongue, a small gape, no teeth in the fore part of the jaws and cheek teeth defective in enamel and of persistent growth. In no other respects does it resemble the edentates; and although it is like the scaly ant-eaters (Pholidota) in having normally articulated vertebrae and a bicornuate uterus, these are characters common to many orders of mammals. The aard-vark is a burrowing, heavily built animal, about six feet long, scantily covered with hair, with a long narrow head carrying huge rabbit-like ears and ending in a swollen mobile snout with termi nal valvular nostrils closed with long hair. The tongue, although long, is not vermiform. The feet are powerful and very much alike except that the fore foot has no first toe ; the toes are long, armed with huge flattened claws, and the second and third, which are the longest, are united by a deep and wide web ; the fore foot is plantigrade, the hind digitigrade. The tail is long, stout and tapering; and the external genital organs are situated on a preanal eminence containing a pair of scent glands opening at the sides of the short penis and of the vulva, which is provided with a cordate flap-like clitoris. The teeth of the permanent set are unlike those of other mammals in being traversed by many tubules radiating from a central pulp cavity. They represent molars and premolars, the latter having milk predecessors ; but in the newly born young traces of incisors and canines which never cut the gum have been discovered. There is evidence indeed that the ancestor of Oryc teropus, before degeneration of the teeth set in, had no fewer than three incisors, one canine, five premolars and five or six molars on each side above and below, a larger number than is found in any order of mammals with typical heterodont dentition.
Aardvarks are found in Africa south of the Sahara both in deep forest and in the open. There are only two or three species known to be in existence.