576 PROF. OWEN ON HYPSIPRYMNODON. 



the interstices of the scales, almost requiring a magnifier for detection. The caudal cuticle 

 is in the form of lacertian scales in many Potoroos ; but in these, as in Lagorchestes, the 

 scales are partially hidden by short decumbent hairs, varying in position in different 

 species ; the scaly tail is most sparingly clothed, and with short stiff hairs, in the sub- 

 genus Potorous, Wth. On the head there are a few scattered supralabial, malar, and 

 superorbital vibrissa?, black, fine in texture, about an inch in length. 



The muffle is nude, as in Bettongia and Potorous, the black naked skin being con- 

 tinued a short way back from the upper part of the nose. The nostrils are lateral, 

 opening close to the terminal nasal disk ; they are curved, with the convexity forward ; 

 the disk is vertically grooved, and projects beyond the mouth. The lateral extent of the 

 oral cleft is 1 inch (26 millims.). Prom the nose-tip to the eye is 1 ineh 5 lines (36 

 millims.). The palpebral cleft is 11 millims. Prom this to the meatus auditorius is 

 22 millims. " The irides are dark hazel "*. The ears are rounded ; 20 millims. long by 

 22 millims. broad; the upper margin is slightly deflected. The basal half of the outer 

 surface is clothed with short fine yellowish hairs ; the rest of the auricle is naked. 



The limbs, fore and hind, are less unequal in length than in the Hypsiprymnidce ; the 

 forearm and paw measure 3 inches 2 lines (80 millims.), the leg and hind foot 4 inches 

 9 lines (122 millims.). The trunk does not taper forward, as in the Kangaroos, but 

 maintains a more equable thickness in agreement with the more equal length and strength 

 of the fore and hind limbs. 



The first and fifth digits of the fore feet, (PI. lxxii. fig. 5) though shorter and smaller than 

 the rest, are by no means so reduced as in Perameles ; they retain the general type of those 

 in BTypsiprymnus. The pollex, I, is the shortest ; its claw does not extend beyond the base 

 of the fore finger n. The little finger, v, attains the distal end of the proximal phalanx 

 of the finger, iv. The mid digit, in, exceeds the adjoining ones by nearly the length of 

 its claw. The claws are small, subcompressed, subdecurved, not broadened above, as in 

 Macropus. The short hairs of the hand terminate at the base of the digits, the dorsal 

 tegument of which is smooth and scaly. On the palmar side of the hand the hairs cease 

 at the proximal border of the palm. This presents a pair of unequal longitudinally 

 oblong callosities, and, in advance of these, three smaller ones near the base of the digits 

 II, iv, and v respectively. The longer hairs of the fore limb shorten, but less abruptly 

 than in the hind limb, at about a third of an inch from the wrist. The callous pad 

 beneath the hind foot extends from the base of the toes backward to the end of the 

 heel, reducing the coating of short and adpressed dark brown hairs to a part of the 

 upper surface. 



The chief gradatorial toe, woodcut, fig. 3, iv, is not so disproportionately long and strong, 

 nor is the fifth toe so weak, as in the Kangaroos and the more Kangaroo-like Potoroos. 

 In the Hypsiprymnidce the proportions are most nearly approached by the species Potorous 

 murinus. The claw of digit iv has not the three-sided hoof-like character of that of the 

 Kangaroo ; it is subcompressed, shorter and deeper than the cleansing-claws of n and in. 



The longer hairs of the leg terminate abruptly half an inch above the tarsus, like 



* Tom. cit. p. 34. 



