548 PROFESSOR OWEN ON THE SPECIES OF PHASCOLOMYS. 
In an old male Tasmanian Wombat their basal breadth equals three fourths of their 
length (Pl. LI. fig. 4)'. The outer angles of the base are divided from the lacrymal 
tubercle (73) by a fronto-maxiilary suture (11-21) 3 lines in breadth. The sides of the 
pair of nasals converge forward at the hinder third, then run parallel, gently curving 
inward, and finally run to the margin of the nostril, with a slight curve outward. Thus 
the course of each lateral border of the nasals is undulate. Their tips extend forward 
about 3 lines in advance of the naso-premaxillary suture (15-22), and are bevelled off 
to an obtuse point from without obliquely inward and forward. Together they form the 
middle third of the upper border of the bony nostril. The frontals (ib. 11) make a slight 
projection into the middle of the fronto-nasal suture (11-15), which from this shallow 
indent runs outward and a little forward to the nasal process of the maxillary (21). The 
naso-maxillary suture (15-21) forms the hind fifth part of the lateral border of the nasals ; 
the naso-premaxillary suture (15-22) runs along the rest of the extent of the nasal bones, 
i. e. to the beginning of their free ends, which are short and subobtuse. 
In a second Wombat the nasals differ in their breadth being equal to three fourths 
of their length, or as 75 to 100, in the absence of any median indent of the fronto-nasal 
suture, and in the sharper convergence of the hinder fourth part of the lateral margins. 
These margins describe a similar wavy course, convex outward along the middle, or a 
little in advance of it. The apices overhanging the nostril are sharper and more pro- 
minent than in the last specimen. 
In a third, somewhat younger Phascolomys vombatus (Pl. LI. fig. 3), the lateral 
margins converge more gradually, and in an almost straight line from the base to the 
anterior fourth of the nasals, where the margins extend nearly straight to the nostril. 
The middle sixth part of the fronto-nasal suture (11-15) is nearly straight or transverse ; 
the rest extends outward and more obliquely forward than in the two preceding spe- 
cimens. ‘The fronto-maxillary suture (11-21) is 4 lines in extent. The nasal apices 
projecting beyond the premaxillo-nasal sutures are sharp and form one fifth the length 
of the whole lateral margin. The basal breadth bears a greater proportion to the 
length of the nasals than in the first-cited skull. 
Phascolomys platyrhinus (P\. LI. fig. 1), in the shortness of the naso-maxillary suture 
(ib. 15-21) and the deep emargination of the fore part of the nasal process of the pre- 
maxillary (ib. 22), is more nearly allied to Phascolomys vombatus than either of these are 
to Phascolomys latifrons’. But the nasal bones of Phascolomys platyrhinus are relatively 
broader than in Phascolomys vombatus; the outer basal angles approach nearer to the 
‘ This proportion is expressed as follows by Dr. Murie in describing his specimen of Phascolomys vombatus. 
“The proportional breadth of the two nasal bones at their hinder ends is to their length, 68 to 100,.”— 
Proc, Zool. Soc. June 27, 1867, p. 802. 
? This relation is well pointed out by Dr. Murie, who remarks that ‘‘ Phascolomys latifrons shears off from 
the common form of Wombat, and reverts to the true marsupial type in several particulars.””—Zoc. cit. p. 800. 
He does not, however, exemplify his ideal type: the postorbital processes are almost peculiar to Ph. latifrons 
among Marsupials. 
