The genus Cuon, or Cyon, has been instituted for the two or three species of Eastern Dogs (C. primaevus, C. dukkunensis, etc.) which agree with each other in the constant loss of a molar in the lower jaw, or, it should be said, almost constant loss, for the missing tooth is occasionally represented. The latter of the two species mentioned, the Dhole, is, like its congeners, an animal which hunts in packs; it is said to hunt even the ferocious Tiger, and to be thus one of the few animals which can face the largest and fiercest of the Carnivora.
The genus Lycaon is a very distinct type, being differentiated from other Dogs by the possession of only four toes on both fore- and hind-limbs, and by the dental formula, which is Pm 4/4 M 2/3. The one species is L. pictus, the Cape Hunting Dog. It is singularly like a Hyaena[[282]] in general appearance; the ochraceous grey ground-colour with black markings and the long ears produce this likeness. The animal has got its vernacular name from the habit of hunting in packs. Its range is over a good part of Africa. The occurrence of this species (or at least genus, for the name L. anglicus has been used) in caves in Glamorganshire seems to show that it is a comparatively recent immigrant into Africa. As to its visceral structures, Lycaon[[283]] does not differ widely from other Dogs. It has, however, no lytta beneath the tongue. The intestines are thus divided: large, 9 feet 1 inch; small, 1 foot 3 inches. This contrasts with the proportions observable in some other Dogs. While other Dogs have but a cartilaginous rudiment of the clavicle, Lycaon has a considerably larger representative of this bone.
Fig. 207.—Fennec Fox. Canis zerda. × 1⁄5.
Fig. 208.—Prairie Wolf or Coyote. Canis latrans. × ⅛.
The bulk of the Dogs, Wolves, Foxes, and Jackals are thus left over for inclusion in the genus Canis. But the numerous
members of this genus can, according to Professor Huxley, be sorted into two series by certain cranial characters. The two series he termed the "Alopecoid" or Fox-like, and the "Thooid" or Wolf-like. It was suggested that the generic name Vulpes be used for the former, and Canis for the second. The characters which will be dealt with immediately are also to be noted among
the Dogs belonging to genera that have already been separated off. Thus Lycaon is distinctly Thooid. The characters in question are these:—In the Fox series, the frontal air-sinus of the Thooids is absent; the cranial cavity is pear-shaped, without an abrupt angle coinciding with the supra-orbital sulcus, such as exists in the other group; the coronoid process of the mandible is rather higher and more turned back in the Foxes, while the depth of the mandible at the level of the first molar is greater.
