384: 



HERBIVOROUS MARSUPIALS 



[Oh. XX. 



which an account will be given in Chapter XXII. When Dr. Falconer, 

 in 1857, pronounced the Plagiaulax to be marsupial and herbivorous, 

 he also regarded it as having the form of a rodent ; but he did not 

 overlook that in some of its characters, especially in the coronoid, 

 it resembled certain predaceous marsupials more than those of the 

 herbivorous class. Professor Owen attaches greater importance to 

 these characters, and he has declared his opinion that the Plagiaulax 

 was carnivorous, or that it fed on small insectivorous mammalia and 

 lizards.* Dr. Falconer objects that the inference as to the preda- 

 ceous habits of Plagiaulax BecMesii, drawn from the upward curve 

 of the incisor (a, fig. 373, p. 383), is neutralized by the more hori- 

 zontal position of the same incisor in the smaller species (a, fig. 374), 



Tig. 374. 



Plagiaulax minor, Falc. 

 (Magnified 4 diameters.) 

 All the teeth in this specimen are in place and well preserved. The hinder part of the jaw- 

 bone, with the ascending ramus and posterior angle, are broken away. 



a, b. Eight ramns of lower jaw, with all the teeth magnified 4 diameters. 



a. Incisor with point brokon off. a'. Impression of same, showing that the inner side 



near the apex was hollowed out in a longitudinal direction. 



b. Offset of coronoid, the rest of which is wanting. 

 m. The two true molars. 



p, m. The four pre-molars. 



c. The first molar, magnified 8 diameters. 



Upper figure, the crown. Lower figure, side view. 



d. Second molar, crown and side view. 



e. Straight line indicating the length of the jaw, natural size. 



to say nothing of the fact that in the living vegetable-feeding Koala 

 (Phascolarctus cinereus) the incisor is also projected forwards with a 

 slight upward inclination, as in P. Becklesii.\ The same anatomist 

 also insists, and apparently with no small force of reasoning, on the 

 analogy of the pre-molar of Plagiaulax {Jc, fig. 373, p. 383), with that 

 of the kangaroo-rat (I, ibid). The reader will see that the grooves in 

 Plagiaulax are close set, perfectly parallel, and that they also corre- 

 spond in number with those of the living hypsiprymnus ; and if he will 

 compare them, as I have done, with the sinuous and bifurcating fur- 

 rows on the pre-molar of the fossil Thylacoleo, to which Professor 



* Owen's Palaeontology, p. 353. 



f Falconer, Geol. Quart. Journ., vol. xviii. p. 357. 



