PROF. OWEN ON HYPSIPRYMNODON. 579 



The length of the tibia in Bettongia penicillata is 3 J inches ; in Hypsiprymnodon it 

 is 2 inches 8 lines. 



The length of the foot-bones in Hypsiprymnus Gilberti (Plate LXXIT. fig. 10) is 

 4 inches 6 lines ; in Bettongia penicillata it is 3 inches 10 lines ; in Hypsiprymnodon 

 (ib. figs. 6 & 7) it is 2 inches 5 lines. 



The entocuneiform bone (ib. figs. 6 & 7, e) is proportionally larger, especially broader, 

 than in the Potoroos in relation to the articulation of the metatarsal of the hallux, i. 

 The rest of the structure of the tarsus adheres, save in the shorter proportion of the bones, 

 to the Poephagous type, exemplified in plate lxxii. of my ' Eossil Mammals of 

 Australia.' 



Mr. Ramsay states that the habitat of Hypsiprymnodon moschatus is the Bockingham- 

 Bay district, and that it frequents the dense and damp positions of the scrubs which 

 fringe the rivers and clothe the sides of the coast-range. Here it is by no means rare ; 

 but, from its retiring habits and the density of the forest, is difficult to obtain. The 

 habits are chiefly diurnal, and its actions, when not disturbed, by no means ungraceful. 

 It procures its food by turning over the debris in the scrubs in search of insects, worms, 

 and tuberous roots, frequently eating the palm-berries (Btycliosperma Alexandres), which 

 it holds in its fore paws, after the manner of the Phalangers, sitting up on its haunches, 

 or sometimes digging. Seldom more than one or two are found together, unless accom- 

 panied by the young. " In March 1874 I obtained from Mr. Broadbent a female with 

 two young in the pouch, very small. During the same month a half-grown young one 

 was shot in company with the adult male and female. They evidently breed, during 

 the rainy season, which lasts from February to May. Both sexes have a strong, although 

 not disagreeable, odour of musk, which appears to be stronger in the female"*. 



In the skins transmitted to me the scrotum of the male was large, and in the usual 

 marsupial prepudendal position t. In the female the orifice of the pouch was in the 

 corresponding part of the abdomen %. Both the size and position of the hind thumb 

 (woodcut, fig. 3) indicate the foot to be a grasper in a much lower degree than that of 

 the Phalangers and Opossums. Mr. Pamsay does not, indeed, adduce any instance 

 from his own or his correspondent's observations of the opposition, or the mode of oppo- 

 sition, of the hallux to the other digits in the act of seizing or of climbing. Although it 

 might be inferred, if the fruit of the JPtychosperma Alexandres was plucked from the 

 branch and not seized after falling to the ground, that Hypsiprymnodon attained it 

 by climbing. 



Even in that case the act would seem to be occasional or exceptional; and the sum of 

 the evidence tells for the ground-dwelling habits of this small and interesting Marsupial. 

 The hallux here is, indeed, of more moment to the biologist in its homological than in 

 its teleological relations. It points, as in the case of more rudimental and useless parts 

 in other species, to the ancestral type. 



Hypothetically, the earliest Marsupials are assumed to be pentadactyle ; and this 

 assumption is supported by the following facts. The majority of the extinct Marsupials 



* Ramsay, torn. tit. p. 34. f Kate LXXI. fig. 1. + Ib. fig. 2. 



