Page:EB1911 - Volume 05.djvu/384

 placed at the hinder margin of the posterior lobe of the blade, and a broad, low, tuberculated heel, occupying about one-third of the whole length of the tooth. The second molar is less than half the length of the first, with a pair of cusps placed side by side anteriorly, and a less distinct posterior pair. The third is an extremely small and simple tooth with a subcircular tuberculated crown and single root.

Views differ in regard to the best classification of the Canidae, some writers adopting a number of generic groups, while others consider that very few meet the needs of the case. In retaining the old genus Canis in the wide sense, that is to say, inclusive of the foxes, Professor Max Weber is followed. The best cranial character by which the different members of the family may be distinguished is that in dogs, wolves and jackals the post-orbital process of the frontal bone is regularly smooth and convex above, with its extremity bent downwards, whereas in foxes the process is hollowed above, with its outer margin (particularly of the anterior border) somewhat raised. This modification coincides in the main with the division of the group into two parallel series, the Thooids or Lupine forms and Alopecoids or Vulpine forms, characterized by the presence of frontal air-sinuses in the former, which not only affects the external form but to a still greater degree the shape of the anterior part of the cranial cavity, and the absence of such sinuses in the latter. The pupil of the eye when contracted is round in most members of the first group, and vertically elliptical in the others, but more observations are required before this character can be absolutely relied upon. The form and length of the tail is often used for the purposes of classification, but its characters do not coincide with those of the cranium, as many of the South American Canidae have the long bushy tails of foxes and the skulls of wolves.

The most aberrant representative of the thooid series is the African hunting-dog (Lycaon pictus, fig. 5), which differs from the other members of this series by the teeth being rather more massive and rounded, the skull shorter and broader, and the presence of but four toes on each limb, as in Hyena. The hunting-dog, from south and east Africa, is very distinct externally from all other Canidae; being nearly as large as a mastiff, with large, broadly ovate erect ears and a singular colouring, often consisting of unsymmetrical large spots of white, yellow and black. It presents some curious superficial resemblances to Hyena crocuta, perhaps a case of mimetic analogy, and hunts its prey in large packs. Several local races, one of which comes from Somaliland, differing in size and colour, are recognized (see ). Nearly related to the hunting-dog are the dholes or wild dogs of Asia, as represented by the Central Asian Cyan primaevus and the Indo-Malay C. javanicus. They have, however, five front-toes, but lack the last lower molar; while they agree with Lycaon and Speothos in that the heel of the lower sectorial tooth has only a single compressed cutting cusp, in place of a large outer and a smaller inner cusp as in Canis. Dholes are whole-coloured animals, with short heads; and hunt in packs. The bush-dog (Speothos, or Icticyon venaticus) of Guiana is a small, short-legged, short-tailed and short-haired species characterized by the molars being only $2 or 1⁄2$; the carnassial having no inner cusp. The long-haired raccoon-dog (Nyctereutes procyonoides) of Japan and China agrees essentially in everything but general appearance (which is strangely raccoon-like) with Canis. The typical group of the latter includes some of the largest members of the family, such as the true wolves of the northern parts of both Old and New Worlds (C. lupus, &c.), and the various breeds of the domestic dog (C. familiaris), the origin of which is still involved in obscurity. Some naturalists believe it to be a distinct species, descended from one that no longer exists in a wild state; others have sought to find its progenitors in some one of the wild or half-wild races, either of true dogs, wolves or jackals; while others again believe that it is derived from the mingling of two or more wild species or races. It is probably the earliest animal domesticated by man, and few if any other species have undergone such an extraordinary amount of variation in size, form and proportion of limbs, ears and tail, variations which have been perpetuated and increased by careful selective breeding (see ). The dingo or Australian dog is met with wild, and also as the domestic companion of the aboriginal race of the country, by whom it appears to have been originally introduced. It is nearly related to a half-wild dog inhabiting Java, and also to the pariah dogs of India and other eastern countries. Dogs were also in the possession of the natives of New Zealand and other islands of the Pacific, where no placental mammals exist naturally, on their discovery by Europeans in the 18th century. The slender-jawed C. simensis of Abyssinia and the South American C. jubatus and C. antarcticus are also generally placed in this group. On the other hand, the North American coyote (C. latrans), with its numerous subspecies, and the Old World jackals, such as the Indo-European C. aureus the Indian C. pallipes, and the African C. lupaster, C. anthus, C. adustus, C. variegatus and C. mesomelas (the black-backed jackal), although closely related to the wolves, have been placed in a separate group under the name of Lupulus. Again, Thous (or Lycalopex), is a group proposed for certain South American Canidae, locally known as foxes, and distinguished from all the foregoing by their fox-like aspect and longer tails, although with skulls of the thöoid type. Among these are the bright-coloured colpeo, C. magellanicus, the darker C. thous, C. azarae, C. griseus, C. cancrivorus and C. brasiliensis. Some of these, such as C. azarae and C. griseus, show a further approximation to the fox in that the pupil of the eye forms a vertical slit. More distinct from all the preceding are the members of the alopecoid or vulpine section, which are unknown in South America. The characteristic feature of the skull has been already mentioned. In addition to this, reference may be made to the elliptical (in place of circular) pupil of the eye, and the general presence of ten (rarely eight) teats instead of a smaller number. The typical groups constituting the subgenus (or genus) Vulpes, is represented by numerous species and races spread over the Old World and North America. Foremost among these is the European fox (C. vulpes—otherwise Vulpes alopex, or V. vulpes), represented in the Himalaya by the variety C. v. montanus and in North Africa by C. v. niloticus, while the North American C. pennsylvanicus or fulvus, can scarcely be regarded as more than a local race. On the other hand, the Asiatic C. bengalensis and C. corsac, and the North American C. velox (kit-fox) are smaller and perfectly distinct species. From all these the North American C. cinereo-argentatus (grey fox) and C. littoralis are distinguished by having a fringe of stiff hairs in the tail, whence they are separated as Urocyon. Again, the Arctic fox (C. lagopus), of which there is a blue and a white phase, has the tail very full and bushy and the soles of the feet thickly haired, and has hence been distinguished as Leucocyon. Lastly, we have the elegant little African foxes known as fennecs (Fennecus), such as C. zerda and C. famelicus of the north, and the southern C. chama, all pale-coloured animals, with enormously long ears, and correspondingly inflated auditory bullae to the skull (see, , ).

Whatever differences of opinion may obtain among naturalists as to the propriety of separating generically the foxes from the wolves and dogs, there can be none as to the claim of the long-eared fox (Otocyon megalotis) of south and east Africa to represent a genus by itself. In this animal the dental formula is i. $3⁄3$, c. $1⁄1$, p. $4⁄4$, m. $3 or 4⁄4$; total 46 or 48. The molar teeth being in excess of almost all other placental mammals with a differentiated series of teeth. They have the same general characters as in Canis, with very pointed cusps. The lower sectorial shows little of the typical character, having five cusps on the crown-surface; these can, however, be identified as the inner tubercle, the two greatly reduced and obliquely placed lobes of the blade, and two cusps on the heel. The skull generally resembles that of the smaller foxes, particularly the fennecs. The auditory bullae are very large. The hinder edge of the lower jaw has a peculiar form, owing to the great development of an expanded, compressed and somewhat inverted subangular process. Vertebrae: C. 7, D. 13, L. 7, S. 3, Ca. 22. Ears very large. Limbs rather long, with the normal number of toes. The two parietal ridges on the skull remain widely separated, so that no sagittal crest is formed. The animal is somewhat smaller than an ordinary fox. In the year 1880 Professor Huxley suggested that in the long-eared fox we have an animal nearly representing the stock from which have been evolved all the other representatives of the dog and fox tribe. One of the main grounds for arriving at this conclusion was the fact that this animal has very generally four true molars in each jaw, and always that number in the lower jaw; whereas three is the maximum number of these teeth to be met with in nearly all placental mammals, other than whales, manatis, armadillos and certain others. The additional molars in Otocyon were regarded as survivals from a primitive type when a larger number was the