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Show 800 DR. J. MURIE ON PHASCOLOMYS PLATYRHINUS. [June 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. platyrhinus 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 adverted to in m y former paper. P. platyrhinus possesses the very reverse, 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 tbe present paper is not so much a perfect and detailed 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 m y remarks chiefly to those points elucidating variety or otherwise in its osseous conformation. Besides, the skeleton of the C o m m o n W o m b a t is well known, and has been sufficiently figured by Prof. O w e n * and others ; so that P. platyrhinus, possessing only minor distinctions, needs not lengthened descriptive repetition. Phascolomys latifrons, on the other hand, shears off from the common form of W o m b a t , 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 precludes the necessity of reiteration. As Prof. O w e n 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. platyrhinus 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 intermediate 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 m e were some twenty in all), I have still the satisfaction 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 *r Trans. Zool. Soc. vol. ii. pl. 68. |