MAHSUPIATA. 
1 1 
tioncd group we find a tolerably distinct thumb in the Plms- 
cogali, ii rudimentary thumb iu the Dtisyurux man-aunts , no 
external thumb in I). Mnuyei; but here the internal metatarsal 
bone exists; and, lastly, this metatarsal bone is absent in the 
Thylacinu*. In the herbivorous group, we find the inter¬ 
mediate stages in degradation of tho hind foot, in passing from 
the Phalunyixtidtc through the Pcramt'luhr, to tho Kangaroo 
group. 
The principal modifications of the extremities are expressed 
in the following Table:— 
I. Second and third toes (counting the toe corresponding to the great toe as 
the first) free. 
A. 
B. 
Thumb to the hind foot very small, or wanting 
Thumb distinct. 
Dasyurid.i:. 
Mymccobius. 
DlDKLlMHU.t:. 
II. Second and third toes of the hind feet slender, and 
united in a common integument. 
A. 
B. 
The four limbs of nearly equal length; the hind 
feet short, and furnished with a distinct 
opposeablc thumb. 
The fore limbs distinctly shorter than the hind, 
which are much det eloped—the foot long. 
a. Hind foot haring an inner mctastarsal 1 , and 
sometimes one, and even two 2 , of the 
phalanges of the thumb, or inner toe; 
fore feet with the outer toes rudimentary 
and nailless, or wanting 
b. No inner metatarsal bone; fore feet with 
all the toes well developed, and haring 
claws. 
i PlIALANGISTID.il. 
j Phascolomy*. 
Peramelid.e. 
Macroi*odid.e. 
The mutual relations of the different genera of marsupials. 
1 Chceropus, no doubt, forms an exception. 
• Professor Owen has observed a seccnd phalanx to the inner toe of the hind 
foot, of a spedes of Perameles, the terminal phalanx being divided by a longi¬ 
tudinal fissure at the extremity, as in the nail-bearing phalanges of the other 
toes. This is remarkable, since such a structure would lead one to suppose 
the inner toe in this animal had a nail: in no marsupial have I yet met with a 
nail to the inner toe in question. 
