MACROPODIDZ 169 
that it was a huge species of jerboa. Soon afterwards (1791) Dr. 
Shaw very properly formed a new genus for its reception, which 
he named Mucropus, in allusion to the peculiar length of its hind 
foot. By the name thus formed, Macropus giganteus, this kind of 
Kangaroo has ever since been known in zoological literature. It is 
the common Gray Kangaroo, called “boomer,” “forrester,” or “old 
man” by the colonists, and frequents the open grassy plains of the 
greater part of eastern Australia and Tasmania; a figure being 
given in the woodcut on p. 160. The muffle is partly covered 
with hair, and the fourth premolar very short. Several varieties 
are known. 
A sub-group, distinguished from the above by the naked 
muffle, includes some very large and handsome species, which prin- 
cipally dwell in rocky mountain ranges, as M/. rufus, the great Red 
Kangaroo, M. antilopinus, and Jf. robustus. The fourth premolar is 
of large or medium size in these forms. Remains of J/. giganteus 
occur fossil in the Pleistocene of Australia, where we also find the 
allied extinct Jf. titan, which attains somewhat larger dimensions. 
Af. robustus also dates from the same geological epoch, where it was 
accompanied by two allied types known as JV. altus and JJ. cooperi. 
The second group includes the larger Wallabies, which are 
smaller than the true Kangaroos, with a brighter and more 
variegated coloration. The palate is generally more incomplete 
than in the typical group; and in the molars the anterior talon is 
connected with the first transverse ridge by an external instead of 
a median longitudinal bridge. The members of this group are 
frequenters of forests and dense impenetrable brushes and scrubs, 
and hence are often called Brush Kangaroos, though a native name, 
“Wallaby,” is now generally applied to them. There are several 
species, of which MV. ruficollis, MM. ualabatus, M. perry, and AL. agilis 
are the best known. 
M. ualabatus and AM. parryi ave found fossil in the Pleistocene 
deposits of Australia. In those beds we also meet with remains of 
several very large extinct species, which appear to be allied to those 
Wallabies in which the fourth premolar is large and elongated, all 
of them agreeing with the Wallabies in the absence of the median 
bridge between the first ridge and talon of the molars. These fossil 
forms comprise M. brehus, in which the skull was probably about 
one foot in length, and JZ. rechus, and Af. anak, which were of some- 
what inferior dimensions. In the last-named species the length of 
the fourth upper premolar is equal to that of the first and half of 
the second molar.+ 
The third and last group of the genus includes the small 
1 For the characters of these species and the undermentioned distinct genera, 
see Owen’s Extinct Mamials of Australia (1877), and Lydekker’s Catalogue of 
Fossil Mammalia in the British Muscum, pt. v. (1887). 
