78 



PEOFESSOE OWEN ON THE FOSSIL MAMMALS OF AUSTEALIA. 



2 inches 7 lines ; the antero-posterior extent of the upper part of the premaxillary, or 

 of the naso-premaxillary, suture (Plate III. between is & 23) is 2 inches ; the maxillo-pre- 

 maxillaiy suture (ib. between 21 & 22), as it descends, runs forward, reducing that dimen- 

 sion of the bone at the middle of the nostril (22) to 1 inch, whence it expands to 1 inch 

 8 lines, where it contributes to the alveolar border of the upper jaw and to the bony 

 palate ; the pair of incisive or premaxillary palatal foramina, before described (Plate 



III. a), open upon the suture of the premaxillary with the palatal plate of the maxillary. 

 Each premaxillary has three alveoli ; the outlet of the foremost (Plate III. i 1) is 



oval, with the larger end forward, 1 inch in long diameter, 7^ lines across the widest 

 part : this socket rises for nearly 2 inches in the substance of the bone, inclining a little 

 backward and outward to its closed end ; the long axes of the outlets converge forward. 

 The outlet of the second incisor (ib. i 2) is a full ellipse, 4 lines by 3^ lines in the two 

 diameters ; that of the third incisor (ib. i 3) seems to have been of similar size. The 

 breadth of both premaxillaries posteriorly is 2 inches 10 lines ; anteriorly, across the first 

 alveoli, 1 inch 8 lines ; the length of the premaxillary part of the bony palate is 1 inch 

 7 lines. The maxillaiy (Plate II. 21) swells outward as it leaves the premaxillary to 

 form the socket of the great carnassial 4), above which it rises to join the malar (25), 

 the lacrymal (13), the frontal (n), and the nasal (15) bones. Anterior to the root of the 

 carnassial it is perforated by the small antorbital foramen. Behind the carnassial socket 

 the bone extends outward and backward for 1^ inch, forming the lower and fore part 

 of the temporal fossa, and there terminating by a free obtuse convex border (ib. 21'), 

 of similar vertical extent, below the malo-maxillary suture. The corresponding part 

 of the posterior border of the maxillary in Felis is concave. On the inner side of 

 the hinder end of the carnassial socket is that (Plate III. m 1) for the small tubercular 

 tooth, which was preserved in the first described specimen ; the long axis of its out- 

 let forms an open angle with that of the carnassial socket, at the fore part of which 

 the alveolar border of the maxillary is excavated by either a similar socket for a two- 

 rooted tooth, or by two contiguous sockets for two small single-rooted teeth (ib. p 3). 

 I think the first the more likely explanation, in which case the long axis of the outlet 

 of this socket forms an open angle with that of the carnassial one, extending therefrom 

 inward and forward, instead of inward and backward, like the posterior socket. The 

 extent of such axis is 6 lines, the first subcircular orifice being rather less, the next 

 rather more than 3 lines in diameter. The fore part of this socket is near the lower 

 end of the maxillo-premaxillary suture, and the state of the alveolar and contiguous 

 palatal part of the jaw here precludes any clear determination relative to a canine ; 

 such a tooth (ib. c), of small size, conical and obtuse, had been cemented to this broken 

 part of the alveolar border, in the line of the small posterior incisors. 



The posterior part of the maxillary is concave as it rises from the border to form the 

 fore part of the temporal fossa, and then bulges out into that fossa as a smooth con- 

 v«-xity, on the inner side of which is the hinder opening of the suborbital canal (Plate 



IV. fig. 3, o). Above this convexity the lower and fore part of the orbit impresses that 



