25G 



fore end, from the tips of the nasal bones (is) to the first incisive alveoli (i 1), is 6 inches 

 lines. The breadth of the face at the outsides of the antorbital foramina is 2 inches 

 G lines ; the same dimension across the nasal processes of the premaxillaries (22") is G inches. 

 The length of the facial part of the skull from the antorbital foramen (Plate XXXVI. 

 fig. 1, 21) to the fore part of the premaxillary (22 ) is 5 inches 8 lines. 



The nasal bones (15) appear to expand as they advance, chiefly transversely, for four 

 fifths of their extent, then abruptly contract, from their outer borders, to terminate in 

 a slightly deflected obtuse apex : their mesial suture appears to lie in a longitudinal chink 

 or depression at the anterior third (Plate XXXVII. fig. 2, is), but the chink does not 

 extend to the conjoined apices. The sides of the most expanded part of the external 

 nostril, contributed by the premaxillaries, swell into low and large, rather rough, tube- 

 rosities (22") ; between these the upper surface is almost flat, like a platform. 



The premaxillaries (as), which unite with the nasals (is), as in Phascolarctos (Plate 

 XXXVI. fig. 3) and Phascolomys (ib. fig. 4), send their nasal processes upward, outward, 

 and forward, where they expand and terminate, each in a tuberosity which projects below 

 and a little in advance of the one above mentioned. These tuberosities, with the mesial 

 prominence of the apices of the nasals, give a trilobate character to the upper boundary 

 of the external bony nostril in Nototherium (fig. 2), exaggerating that in Phascolomys 

 (%. 4). 



The premaxillaries (22) contract and descend, below the nasal processes, as vertical 

 plates ; slightly expanding again, below, to form the alveoli of the incisors, especially of 

 the larger anterior pair : the outer surface of these alveoli appears to have been coarsely 

 rugous. The inner walls of the alveoli rise, conjoined, as a vertical plate of bone, 

 3 inches above the outlets, and extend backward in close contact to form or support the 

 beginning of the " septum narium." The space between the premaxillary septal plates 

 and the superincumbent ends of the nasals is little more than an inch, which gives the 

 vertical diameter of the nostril at that part ; its transverse diameter is 4 inches. The 

 antero-posterior extent of the alveolar part of the premaxillary is 2 inches 6 lines. The 

 fore-and-aft diameter of the outlet of the first incisor is 1 inch 2 lines; the transverse 

 diameter is 10 lines. The outlets of the smaller second and third incisors are subcir- 

 cular ; each has a diameter of 6 lines. 



The cranial characters above described from casts, drawings, and photographs, I have 

 been enabled to test by actual fossils of portions of the upper jaw and skull. 



The first of these is a fragment of a right maxilla with two molars (m 1, m 2) in situ. 

 It shows part of the front pier of the maxillary arch, including its posterior surface, 

 which springs from the alveolar plates on the vertical parallel with the interval between 

 the two lobes of m 1, at its lower end, and extending as it rises with a curve convex back- 

 ward to overhang part of the hind lobe of the same tooth. Sufficient of this maxillary 

 zygomatic process remains to exemplify the difference between Nototherium and I)ipro- 

 tddon in the antero-posterior extent or thickness of this " pier ;" it is characteristically 

 greater in the smaller Herbivore, and of itself would save the palaeontologist from 



