PHASCOGALE. 
405 
In P. Swainsonii, P. Jlavipes l , and P. leucogastet 9 the 
third is the largest of the premolars in the upper jaw, and is 
rather smaller than the preceding two, in the lower jaw. 
P. leucopus , P. albipcs, and P. crassicaudala , differ from 
the above only in having the second and third premolars of 
the lower jaw equal. 
With regal’d to the true molars, those of the upper jaw 
differ from the true molars of the Marsupial animals already 
described, in having the crown of a triangular form, a form 
of the masticating surface in these teeth which runs through 
the remaining species of the order. In the herbivorous 
species we have found the crowns of the true molars ap¬ 
proaching more or less to a square form, and the same form 
was found in some of the insectivorous species forming the 
genus Perameles; in other members of that genus, however, 
owing to the reduced size of the posterior internal lobe, the 
masticating surface of the molars approximated to the tri¬ 
angular form. Now if we compare the true molar teeth of 
Phascogalc with these species of Perameles, we shall find that 
the chief difference consists in the absence of the posterior 
internal lobe in the Pliascogale. Another point of distinction 
in the molar teeth of the two animals is observable in the 
number of prickly tubercles arranged along the outer side of 
the tooth, there being four in Perameles, and but three in 
Phascogale: it is the foremost of the four, in Perameles 
(which is the smallest), which is lost in Phascogale, or of 
which there remains only an indistinct trace 2 . 
1 In the immature animal, when the skull presents but three true molars on 
either side of the jaws, the third, or hindermost, of the upper and lower pre¬ 
molars is a minute tooth in P.flavipeSj and probably in other species; it is 
then a milk tooth, and therefore to be replaced by another. 
2 In the true molar teeth of the species of Perameles I find very evenly 
developed all the cusps, or pointed tubercles, which arc found in Insectivorous 
