Tertiary.] PALAEONTOLOGY OF VICTORIA. [Mammalia. 



PLATE LXX. 

 PHASCOLOMYS (SPECIES). 



[Genus PHASCOLOMYS (Geoff.). (Sub-kingd. Vertebrate. Class Mammalia, Order 

 Marsupialia. Sub-order Diprotodontia. Fam. Phascolomidae.) 



Gen. Char. All the teeth with long curved hollow bases, without solid fangs ; incisors, 

 I ; canines, g ; premolars, ; molars, . Incisors scalpriform ; the molars, except the first, are 

 divided each into two nearly equal parts by a very deep inflection of the enamel on the outer 

 side, and a shallow inflection on the inner side in the lower jaw, and the deeper inflection in the 

 inner side in the upper series. Body short, thick ; tail rudimentary ; head large, depressed ; 

 eyes and ears small ; legs short, nearly equal ; anterior feet, with five short stout toes, each 

 with broad solid little-curved claws ; hind feet with five toes, of which the inner one is very 

 small, without claw, and placed at right angles to the others, which have curved claws, hollow 

 below ; the three middle toes joined. Confined to Australia in the recent and fossil state.] 



DESCRIPTION. Pelvis : sacrum of four anchylosed sacral vertebrae, the dia- 

 pophyses dilated at their ends and anchylosed tog-ether by their distal thirds ; the 

 whole of the first and second and the anterior half of the third articulating- with 

 the ilia ; the diapophyses of the fourth vertebra are smallest and produced forward 

 to anchylose with the ends of those of the third vertebra. The three following- 

 caudal vertebrae with broad diapophyses dilated at the outer ends, the two last, or 

 second and third, anchylosed together by their distal ends. Length of bodies of 4 

 sacral vertebrae 4 inches 2 lines, width across distal ends of diapophyses of second 

 sacral vertebra 2 inches 9 lines ; length of articulation with ilium 2 inches 5 lines, 

 width 10 lines ; length of three following- caudal vertebrae 2 inches 1 line j 

 width across diapophyses of third caudal vertebra 2 inches 7 lines ; height from inner 

 surface of body to top of neural spine of 1st sacral vertebra 1 inch 5 lines j cor- 

 responding- measurement of 2nd sacral vertebra 10 lines, 



The vertebral bones forming the sacrum are singularly diverse 

 in each of the living species of Wombat or Phascolomys, and were 

 supposed to afford good specific characters, but I find the variations 

 of individuals of each species so great that I attach no value to 

 characters which, without this experience, might seem specific. 



Professor Owen was the first, in his memoir " On the Osteology 

 of the Marsupialia" (Trans. Zool. Soc., v. 8) to point out 

 the singular differences in the sacrum of the three living 

 species of Wombat known to him ; and as he has remarked that 

 " the endeavour to restore the lost species of Wombat presumes a 

 power of recognising the bones or portions of bones when dis- 

 covered in a fossil state ; and that this can only be acquired by a 

 knowledge of the characters of the corresponding bones of the 

 existing species," I figure the sacrum and os innominatum of a 



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