‘ MARSUPIALIA. 
veloped, and the conjunctiva covering its free 
margin is stained black. 
In the Kangaroo I found the dark pigment 
on both the inside and outside of the choroid, 
and the ciliary processes very well developed. 
The lens is proportionally large. In the dead 
Kangaroo the radiated muscle of the iris is 
much contracted, and the pupil widely open. 
Beneath the upper eyelid in the Kangaroo 
there is a cartilaginous ridge having the con- 
junctiva reflected over it. 
Organ of taste—The tongue is well deve- 
loped and freely moveable in all the Marsu- 
pialia, and the epithelium covering the simple 
papille of its dorsum is never condensed into 
spines. In the carnivorous species, as the 
lasyuri, the conical papille are minute and 
soft, but directed backwards so as to givea 
slight roughness to the tongue when stroked in 
the opposite direction. Under a lens they 
appear like fine shagreen. Near the base of 
the tongue in Dasyurus viverrinus there are 
three fossulate papille, in triangle, with the 
apex towards the epiglottis. There is a small 
lyita beneath the tip of the tongue. 
In the Perameles, besides the minute and 
generally diffused simple papille, there are 
others of larger size, placed at distances of 
nearly a line apart, and raised about a third of 
a line above the surface of the dorsum. The 
fossulate or glandular papille correspond in 
number and arrangement with those of the 
Dasyures, but the entire tongue is relatively 
longer and more slender, especially in Per. 
lagotis. 
In some species of Opossum, as Didelphys 
Philander, the margin of the tongue is fringed 
with a series of fine long papille. 
In the Phalangers there is a thickening at 
the edge of the frenum lingue, but no true 
lytta. The dorsal papille resemble those of 
the Dasyures, but are somewhat more obtuse. 
In the Kangaroo there is a callous ridge 
along the middle of the under surface of the 
free extremity of the tongue, and a corresponding 
furrow along the dorsum; the latter is common 
to all the Marsupials. In the Wombat and 
Koala the dorsum of the tongue rises some- 
what abruptly from a furrow surrounding its 
base; its form is narrow, moderately deep, 
diminishing in this respect to the tip, which is 
rounded. In both the Kangaroo and Koala 
there is a single large fossulate papilla near 
the base of the tongue. ‘ 
The palate is sculptured in most Marsupials 
with transverse ridges. These are most nume- 
rous in the Bandicoots, being fourteen in the 
Perameles nasuta, and are slightly curved for- 
wards. The roughness thus produced must aid 
the tongue in retaining small insects. 
Dicestive System. 
Mouth.—The various modes of locomotion, 
resulting from the different modifications of the 
osseous and muscular systems observable in the 
several families of Marsupialia, relate to the 
acquisition of as various kinds of alimentary 
substances, which necessarily require for their 
assimilation as many adaptations of the diges- 
tive organs, 
297 
Food,—means of obtaining it,—instruments 
for preparing and mechanically dividing it,— 
cavities, canals and glands for chemically 
reducing and animalizing it,—form a closely 
connected chain of relationships and interde- 
pendencies. The usual sequence of anatomical 
description has here been followed in com- 
mencing with the consideration of the passive 
and active organs whose office it is to carry the 
stomach to the food and the food tothe mouth, 
and we have now to describe the preparatory 
mechanical instruments in digestion, and the 
modifications and appendages of the alimentary 
canal. 
Thejaws of the Marsupialiaare covered by well- 
developed fleshy lips ; the upper lip is partially 
cleft in the Kangaroos, as in some of the Ro- 
dents; the muzzle is clad with hair in the 
Great Kangaroo and a few other species of 
Macropus, but in other Marsupialia it is naked 
and generally red from the vascularity of the 
integument. 
The masticatory muscles of the jaws consist 
in the Marsupial, as in other Mammalia, of the 
temporal, the masseter, the external and in- 
ternal pterygoids, and the digastricus. They 
are chiefly remarkable for the large proportional 
size of the masseter and internal pterygoid; the 
great developement of the latter muscle is con- 
stant in all the Marsupials, and is the condi- 
tion of the peculiarly large and inflected angle 
of the lower jaw. The relative size of the 
masseter, as compared with the temporal mus- 
cle is greater in the herbivorous than in the 
carnivorous species, but this difference is 
much less in the Marsupial than in the cor- 
responding placental genera. The extent of 
origin of the temporal muscle is indicated by 
the various conditions of the temporal and pa- 
rietal crests ; the inner surface of the zygomatic 
arch always affords origin to a portion of the 
fibres of this muscle, and in some species, as 
in the Koala, to all that portion of it which is 
inserted into the external fossa of the coronoid 
process and ascending ramus of the jaw, the 
fibres from the temporal and parietal bones 
being implanted on the inner side of the coro- 
noid process. The masseter takes its origin by 
a strong band of tendinous and carneous fibres 
from the inferior and anterior part of the zy- 
goma ; the muscle expands as it is directed 
backwards, and is inserted into the ridge which 
bounds the external temporal fossa of the as- 
cending ramus, and into the outer side of the 
inflected angle of the outer jaw. The erternal 
pterygoid takes its origin from the temporal 
plate of the sphenoid and the base of the 
pterygoid plate anterior to the sphenoidal 
bulla; the fibres converge to be implanted 
into the inner projecting side of the condyle 
of the jaw. The internal pterygoid arises 
from the outer depression of the longitudi- 
nally extended pterygoid plate already men- 
tioned as characterizing the cranial structure 
of the Marsupials, and is implanted along the 
inner surface of the inflected angle of the jaw. 
The digastricus arises from the ex-occipital 
process ; its fibres expand, and are inserted 
into the lower margin of the maxillary ramus, 
anterior to the commencement of the inflected 
