192 



PEOFESSOR OWEX OX THE FOSSIL mMMALS OF AUSTEALIA. 



2, q) Wombats. The extent of the molar series and the sizes of the individual teeth 

 accord, save in the narrower character of the lower molars, Avith the teeth of the upper 

 jaw in the subject of figure 5, Plate XVII. If these fossils are maxillary and mandibular 

 specimens of the same species of Wombat, the lower molars are relatively narrower trans- 

 versely, compared to the upper ones, than in any of the existing species. 



In the mandibular specimen under consideration we see combinations of characters 

 confined seA^erally to distinct species in existing Wombats. I am disposed therefore, 

 and for reasons above assigned, to refer this mandibular fossil, with the maxillary one 

 above cited, to Phascolomys MitchellL 



A second similar specimen of left ramus, including part of the symphysis and of the 

 ascending ramus, has a molar series 2 inches in extent, and, as in fig. 5, Plate XIX., the 

 teeth have the general characters of those \\\ Phascolomys latifrons; they are trans- 

 versely narrower than in Phascolomys vombafus or Phase. pJatyrhinus. The ectocrota- 

 phyte depression is deeper than in the perforate mandible of that species ; the perfora- 

 tion {p) here shows a similar position and size. The depth of this fossil jaw at the back 

 part of the symphysis is 1 inch 5 lines. The symphysis terminates below the interval, 

 between the second {d *) and third [m \) molars. The ectalveolar groove is wider than 

 in the subject of fig. o, Plate XIX., but is deeper than in the Platyrhine and Tasmanian 

 Wombats. The symphysis is not bilobed behind, as in fig. 6, Plate XXI. ; but this and 

 the before-mentioned differences from that subject probably exemplify the range and seat 

 of variety in the mandibular characters of one and the same species. 



The characters noted in the subjects of figs. 4 & 5, Plate XXIII., of fig. 4, Plate 

 XXI., and of figs. 2 & 3, Plate XX., are of specific value; but, as in the maxillary 

 fossils (Plate XVII. figs. 1 & 2), I do not feel grounds for indicating, after comparison of 

 the mandibular fossils from the Wellington-Valley breccia-caA^es, more than tAvo species 

 of a size not exceeding the known existing Wombats, and not referable thereto. 



§ 15. Jfandibular characters of Phascolomys Thomsoni, Oiv. — From the freshAvater 

 deposits of Queensland I haA^e received mandibular fossils of the genus Phascolomys, 

 AA-hich, Avith decrease of size, sIioav characters not in accordance with those of any of the 

 cave fossils. 



The subject of figs. 8 & 9, Plate XVIII., and fig. 7, Plate XXI., is a right mandibular 

 ramus, Avith slight mutilation at both ends. In the loAA^r contour of the jaAV, the depth of 

 the cctocrotaphytc depression (/'), the breadth of the ectalveolar groove (?f), the position 

 and size of the intercommunicating foramen (p), the shape of the anterior molar (d 3), 

 and the shape and proportions of the incisor (i), so far as these are indicated, the present 

 fossil agrees Avith Phascolomys platyrhinus, and differs from Phascolomys latifrons and 

 Phase. Mifrhclli. It agrees, hoAvever, Avith these, and differs from both the bare-nosed 

 AVombats, in the relative position of the back part of the sympliysis (Plate XXI. fig. 7, .s'}, 

 Avhifli does not extend beyond tlie vertical line dropped from the front lobe of ?n 1. 



The; grinding-surface of d 3 (Plate XVIII. fig. 9) is an ellipse Avitli the long axis nearly 

 parallel Avith that of the mandible. The outer side of the incisor is transversely convex, 



