800 DR. J. MURIE ON PHASCOLOMYS PLATYRHINUS. [JuDC 27, 



Wombat some are darker than others ; and this fact is seen even in 

 two very young animals of this species in the same collection. 

 Comparison of the Hairy-nosed Wombats shows also that some of 

 them assume a browner hue than others. 



There is one point which the recent acquisition of the specimen 

 of P. platyrhimis confirms, namely, the entire absence of the grizzly 

 greyish tint, which is so very strongly marked and constant in the 

 common species (P. wombat^ 



The peculiar silky structure of the fur of P. latifrons was ad- 

 verted to in my former paper. P. jdatyrhinus possesses the very re- 

 verse, the fur being coarse (almost bristly) to the touch. P. wombat 

 has it of an intermediate fineness. So perceptible is this difference 

 that the three species might almost be identified by touch alone. 



Osteology. — The Skull. 



The object of the present paper is not so much a perfect and de- 

 tailed description of the entire osteology of Phascolomys platyrhinus 

 as of differentiation and specific distinction between it and other 

 forms of the genus ; I have therefore limited my remarks chiefly 

 to those points elucidating variety or otherwise in its osseous confor- 

 mation. Besides, the skeleton of the Common Wombat is well known, 

 and has been sufficiently figured by Prof. Owen* and others ; so that 

 P. platyrhimis, possessing only minor distinctions, needs not length- 

 ened descriptive repetition. 



Phascolomys latifrons, on the other hand, shears off from the 

 common form of Wombat, and reverts to the true marsupial type in 

 several particulars. Its skull has been well illustrated in vol. iii. of 

 our ' Transactions ;' and the graphic seizure of its salient points pre- 

 cludes the necessity of reiteration. As Prof. Owen has there clearly 

 shown, the skull of P. latifrons presents such marked characters as 

 to entitle it to specific distinction solely thereupon. 



But between the skulls of the remaining two (P. platyrhimis and 

 P. wombat) no such clear line of demarcation exists. I find, after a 

 careful reexamination of a more extensive series of crania, that these 

 last-mentioned forms have very close resemblances to each other — or 

 rather, I should say, that they glide together so insensibly by inter- 

 mediate forms that the osteologist might find difficulty in assigning 

 some specimens to their proper species, were it not that size lends 

 aid to the determination. 



Nevertheless, although freely admitting the tendency to gradation 

 observable in a series of skulls of P. platyrhinus and P. wombat 

 (those examined by me were some twenty in all), I have still the sa- 

 tisfaction of finding that such distinguishing characters as I pointed 

 out in the published paper referred to, in the main hold good. But 

 be it observed that while in no ways asserting that the skull of a 

 young specimen of P. platyrhinus can at once and with certainty be 

 distinguished from that of an adult but loosely connected cranium 

 of P. wombat, I have yet reason to believe that with specimens of 

 * Trans. Zool. Soc. vol. ii. pi. 68. 



