346 PROFESSOR OWEN ON THE SPECIES OF PHASCOLOMYS. 
zoologists generally is the more probable since the grand ‘Ostéographie’ of De 
Blainville was interrupted by the regretted demise of the indefatigable author before 
it had reached his subclass DipELPuHys'. 
§ 2. Cranial Characters of Phascolomys. 
The characters of the skull of Phascolomys platyrhinus, briefly defined in the 
‘Descriptive Catalogue of the Osteological Series in the Museum of the Royal College 
of Surgeons’”, have subsequently been determined by Prof. M‘Coy® and Dr. Murie* to 
be those of the continental or Victorian bare-nosed, large, brown or black Wombat. 
A skull of this species, figured of the natural size in Plate LI. fig. 1, gives a length, 
from the hindmost ridge of the occiput to the front border of the incisor-alveoli, of 
8 inches. Another skull in the British-Museum collection exceeds this only by one 
line ; a third is in the same slight degree smaller. The specimen submitted to me by 
Dr. McBain of Edinburgh, in 1855, yielded a length of 8 inches; two other specimens 
have the length of 7 inches 8 lines (Pl. L. fig. 1), and 7 inches 6 lines (Pl. LII. fig. 1). 
Dr. Murie gives minor dimensions of some, probably female, specimens’. 
The occiput (Plate L. fig. 1, 2, 3, & fig. 2) rises vertically from the foramen magnum 
at the median line, but curves a little backward laterally, where it forms the 
sides of the broad superoccipital (ib. fig 2,3). The lower and lateral parts of the 
occiput are formed by the exoccipitals (ib. fig. 2, 2), the mastoids (8 ), and squamosals (27). 
The occiput is higher in proportion to its basal breadth than in Phascolomys vombatus 
(ib. fig. 3); it is more quadrate in form ; it does not curve upward and inward so regularly 
from the mastoid processes (8) to the summit, as in Phascolomys latifrons (ib. fig. 4). 
The composition of the occipital region agrees with that illustrated in Pl. Ixxi. 
fig. 6 (Trans. Zool. Soc. vol. ii.), in Phascolomys vombatus. But the portions con- 
tributed by the squamosals (Pl. L. fig. 2, 27,27), do not reach so low down upon the 
mastoid process as in Phascolomys vombatus (figs. 3, 6, 27,8). The basioccipital 
(Pl. LII. fig. 1,1) contributes about half an inch of the thick lower border of the 
foramen magnum. ‘The exoccipitals (Pl. L. fig. 2,2) form the lateral borders, de- 
veloping there the condyles; and the superoccipital completes the middle of the upper 
border, which is sharp; and as ossification of the latter element does not usually 
extend so low down as to fill up the whole interspace left by the exoccipitals, the 
1 The ‘ Prospectus’ of this work was issued after the reading of my first memoir on the osteology of the 
Marsupialia; see Zool. Trans. vol. ii. p. 379. The character and form of the work, especially the richness 
and beauty of its illustrations, exemplified in the Part which appeared after the communication of my 
second memoir, led me to abandon that subject, as being likely to meet with more complete illustration in 
the ‘ Ostéographie du Squelette et du Systéme Dentaire des cing Classes d’Animaux Vetébrés récents et fossiles,’ 
4to, Paris, 1840-1860. 
2 4to, 1853, vol. i. p. 334, no. 1841. 
+ Transactions of the Royal Society of Victoria, vol. viii. (1868), p. 267. 
* Proceedings of the Zoological Society of London, Dec. 1865, p. 838. * Thid. p. 845, 
