FAMILY II.—ANOMALURIDÆ.
Some curious African animals, closely resembling the Flying Squirrels, and at first regarded as belonging to that group, were formed by Mr. Waterhouse into a distinct genus, which he called Anomalurus, in allusion to the peculiar characters presented by their tail. This organ, which is long and well clothed with hair, although not so bushy as in the true Squirrels, has on the lower surface of its basal portion a double series of horny scales, which project from the skin, and probably serve to assist the animal in climbing upon the branches of trees.
Besides this peculiarity, these animals exhibit certain other characters which have induced modern zoologists to separate them from the Squirrels as a distinct family. Thus, the post-orbital processes are wanting, or nearly so; the infra-orbital openings are large; the molar teeth are four in number on each side, above and below, nearly equal in size, and not tubercular, but with a flat surface, crossed by transverse loops of enamel; and the palate is contracted in front and deeply notched behind. In the skeleton we find sixteen pairs of ribs, whereas in the Squirrels there are only twelve or thirteen pairs; and the internal anatomy, first described by Mr. Alston, is very peculiar. The flying membrane is quite as largely developed as in the Flying Squirrels, and is in the same manner extended from the wrists to the heels, and further supported by cartilaginous spurs starting from the fore limbs; but, whilst in the Flying Squirrels this spur springs from the wrist itself, in the Anomalures it projects from the elbow, and thus produces a still greater extension of the membrane. The ears are well developed, the eyes large, and the general aspect both of head and body completely squirrel-like. Six species of this family have been described, all from the West Coast of Africa. One of them occurs in the island of Fernando Po. The species figured (Anomalurus fulgens) is from the Gaboon. It is a handsome little creature, of a bright reddish colour, paler below, and having a small white spot between the ears. Its length is fourteen inches, and its tail is seven inches long. In some of the other species the tail is as long as the body. Of the habits of these animals little is positively known, but they are said to feed upon fruits. They probably resemble the Flying Squirrels in their general mode of life.
FULGENT ANOMALURE (From the Proceedings of the Zoological Society).
MOLAR TEETH OF THE ANOMALURE.
FAMILY III.—HAPLODONTIDÆ.
This is another small family, smaller even than the preceding one, for it includes only a single known species, limited in its range to the western coast of North America. This is the Sewellel, a little Rodent, first observed by the American travellers, Lewis and Clarke, in 1805 or 1806, described in 1814 by Rafinesque under the name of Anisonyx rufa, and afterwards, in 1829, by Sir John Richardson, as the type of a new genus, as Aplodontia leporina. This generic name has been corrected, in accordance with its derivation, by more recent writers, to Haplodon, from which the name of the family has been formed.
In this animal there are five molars in the upper and four in the lower jaw; the first upper molar is very small, and all these teeth are rootless, simple, and prismatic, the surface of each tooth being surrounded by a mere border of enamel. The skull is very flat, very wide behind, and furnished with large zygomatic arches; between the orbits and in front it is much contracted, and there are no post-orbital processes. In the lower jaw the angular portion is twisted so as to form a horizontal ridge. The body is stout and clumsy, the tail very short, and the claws of the fore feet (which are five-toed, as well as the hind ones) are very powerful; in fact, as Dr. Coues says, “The whole organisation, viewed externally, indicates terrestrial and highly fossorial habits.”