320 PROF. OWEN ON THE CLASSIFICATION 
cond and third digits counting from the inside, and the sudden increase in length and 
strength of the third and fourth digits, which are chiefly subservient to locomotion. 
In consequence of the inequality of length in their extremities, the mode of progression 
in the Bandicoots is by bounds ; the hind and fore-feet being moved alternately as in 
the Hare and Rabbit ; and the crupper is raised higher than the fore quarter. The teeth 
which offer the greatest range of variation in the present genus are the external or pos- 
terior incisors and the canines: the molars, also, which originally are quinque-cuspi- 
date, have their points worn away, and present a smooth and oblique grinding surface 
in some species sooner than in others. 
The Bandicoots which approach nearest to the Myrmecobius in the condition of the 
incisive and canine teeth are the Perameles obesula and P. Gunnii. There is a slight 
interval between the first and second incisor, and the outer or fifth incisor of the upper 
jaw is separated from the rest by an interspace equal to twice its own breadth, and 
moreover presents the triangular, pointed, canine-like crown which characterizes all the 
incisors of Myrmecobius ; but the four anterior incisors are closely arranged together and 
have compressed, quadrate, true incisive crowns. From these incisors the canine is 
very remote, the interspace being equally divided by the fifth pointed incisor, which 
the canine very slightly exceeds in size. In Peram. nasuta the incisor presents the same 
general condition, but the canines are relatively larger. 
The marsupial pouch in the Bandicoots, at least in the full-grown females of Per. na- 
suta, Per. obesula, and Per. Lagotis, has its orifice directed downwards or towards the 
cloaca, contrariwise to its ordinary disposition in the Marsupials : this direction evidently 
relates to the position of the trunk when supported on the short fore and long hind legs. 
In the stomach and intestines of a Perameles nasuta Dr. Grant found only the remains 
of insects ; and in the examination of the alimentary canal of a Per. obesula I obtained 
the same results. Nevertheless the Perameles Lagotis now living in the Society’s Me- 
nagerie refuses meat and meal-worms, and subsists on vegetable food exclusively. 
Genus Cheropus. 
The singular animal on which Mr. Ogilby has founded this genus is briefly noticed 
and figured in Major Mitchell’s Australia, (vol. 11. pl. 38. p. 131.) and the individual 
described is preserved in the Colonial Museum, at Sydney, N.S. Wales, (No. 35. of Mr. 
George Bennett’s Catalogue). It would appear that the two outer toes of the fore foot, 
which are always very small in the true Bandicoots, are entirely deficient in the Chero- 
pus, unless some rudiments should exist beneath the skin; at all events only two toes 
are apparent externally, but they are so developed and armed as to be serviceable for 
burrowing or progression. The inner toe is wanting on the hind foot. Dental formula: 
: 44 ee — ae 
Incisors 3-3 } Camines | 3 premolars ae molars fa 46. 
All the teeth are of small size ; the canines resemble the spurious molares in size and 
