204 MAMMALIA ORDER XI.MARSUPIALIA. 



Australian diprotodont marsupials (Phascolomyidce). They are clumsily-built 

 animals, differing from all the members of the group hitherto mentioned 



by their burrowing habits ; and they may be regarded as 

 Wombats. occupying among the Australian fauna the position held in 



other regions by the burrowing rodents. Curiously enough, 

 they also approximate to the latter order in the nature of their dentition, 

 the incisors being reduced to a single cutting pair in each jaw, behind which 

 comes a long gap, without any canines, till the cheek-teeth are reached. 

 Stout and clumsy in form, the wombats have a short and broad muzzle ; 

 thick, short, and strong limbs of nearly equal length in front and behind ; 

 the fore-feet with five nearly sub-equal and powerfully-clawed toes ; the first 

 hind-toe short and clawless, the remaining toes of the same foot having strong 

 and curved claws, and the second and third imperfectly united by a common 

 skin ; and the tail rudimental. Internally, the stomach is simple, and the 

 intestine is furnished with a caecum. The teeth are rootless throughout life ; 

 the large, curved, and chisel-like incisors having enamel only on the front 

 and sides ; and the five pairs of cheek-teeth are strongly curved, the molars 

 consisting of two lobes, but the pre- molars with only one. As regards their 

 habits, it will suffice to say that wombats are harmless, inoffensive animals, 

 burrowing deeply in the ground, and subsisting on the roots which they thus 

 disinter. They are entirely nocturnal, never issuing from their holes till 

 evening, and returning to them with the first rays of morning. 



A distinct family (Epanorthidce) is now represented solely by two small rat- 

 like South American animals, which, from the estate where the second 



example was obtained, may be known as the selvas. One was 

 Selvas. originally described and referred to the present order under 



the name of Hyracodon fidiginosus, in the year 1863, upon 

 the evidence of a specimen obtained in Ecuador ; but the description was 

 so insufficient that naturalists had no clue to its affinities. In the autumn 

 of 1895 a second example was obtained from Colombia, which showed that it 

 indicated a type of marsupial hitherto known only from fossil forms occurring 

 in the Tertiary rocks of Patagonia, which have been described under the 

 names of Epanorthus, Abderites, etc. As the name Hyracodon had been 

 previously employed for an extinct genus of mammals, the selvas were at 

 the same time re-christened Ccenolcstes. 



The selvas have an elongated skull somewhat like that of the Australian- 

 bandicoots, with four pairs of upper incisor teeth and a large pair of canines, 

 and thus resemble the Polyprotodont type. In the lower jaw there is, 

 however, a single pair of horizontally- projecting lower incisors, not unlike 

 those of the kangaroo, behind which are several pairs of small functionless 

 teeth representing the other incisors, canine, and earlier pre-molars. In 

 both jaws the four pairs of molars are oblong teeth, with four blunt cusps, 

 and thus totally unlike the corresponding teeth of the opossums and other 

 members of the Polyprotodont sub-order. The feet are of normal type, with 

 five toes each, of which the first appears to be opposable in a limited degree 

 to the others ; and the rat-like tail is partially prehensile towards the 

 extremity. Externally, the selvas look very like small, blackish rats, with 

 a sharp nose. 



In all probability, these animals and their extinct allies are descendants from 

 a group of Polyprotodont Marsupials whose remains are found in the Tertiary 

 deposits of Patagonia, and whose ancestors reached South America by means 

 of a land connection perhaps by way of the Antarctic continent with 



