100 ON AN EXTINCT MAMMAL ; 
which attained nearly the dimensions of an elephant, to Stheno- 
merus, which may have been as large as a small bullock. ‘Their 
food was probably the coarser vegetation of the lake and marsh 
and the branches of such trees as were accessible to them ; their 
habitats accordingly were the great river valleys of the period and 
the dense humid forests on their slopes. Restricted perhaps to 
the latter was the subject of the notes now offered— 
MARSUPIALIA—PHYTOPHAGA 
SEC. DIPROTODONTINA 
FAM. DIPROTODONTIDE 
GEN. Nov. OWweENIA.* 
DENTITION Zz 2, c8, pmi, m4. 
DENTAL AND CRANIAL CHARACTERS.—The anterior incisors 
above and below as tusks, similar in size, shape and curvature ; 
posterior upper incisors subrudimentary ; nasals small, retracted ; 
zygoma slender, retreating; mandible elevated anteriorly, sym- 
physis inclined at a high angle. 
OWENIA GRATA.—The anterior upper incisors divergent, strong 
at the base, rapidly tapering, towards the apex curving distad and 
caudad, rounded on the outer sides, a little flattened on the inner, 
but strengthened here by a broad low buttress ascending on the basal 
half, tumid on the inner posterior side, surface of wear commencing 
on the anterior edge of the apical third of the inner side (leaving 
the enamel of the outer side as a sharp edge passing caudad over 
the apex), thence curving dorsad and distad to the middle of the 
posterior side on which it is rather deeply excavated. On the 
outer side and near the base of each tooth, a broad sub-horizontal 
groove alike in shape, position, depth, and smoothness and in all 
probability surfaces of wear. 
Posterior upper incisor, 7. 37 distant 4 mm. from the- great 
incisor, small, with a long columnar crown sloping and curving 
* It is so clearly demanded by the fitness of things that the name of the 
expositor of the Extinct Mammals of Australia should have place in their 
nomenclature, that its occurrence more than once in our invertebrate lists 
fails to deter one from asking that it may be accepted where it has so much 
claim to acceptance. 
+It seems to the writer probable that the missing incisor is the middle 
one i. 2, always in diprotodont marsupials, the feeblest, and from its position 
liable to expulsion by an excessive development of either of its neighbours. 
The monopoly of function here obtained by the anterior incisor has had its 
own result—the enfeeblement of the remaining tooth. 
