MARSUPIALIA. 
lateral and posterior part of the penis, until it 
is inserted with the opposite muscle at the 
base of the glans. 
In the Opossum and those Marsupials 
which, having a bifid glans, enjoy, as it were, 
a double coitus, there is a levator penis (f, f, 
fig. 136), which is not present in the Kangaroo. 
Each portion of this muscle takes its origin 
from the fascia covering the crus penis, con- 
verges towards its fellow above the dorsum 
penis, diminishing as it converges, and termi- 
nates in a common tendon inserted into the 
pe part of the base of the glans. 
here is another powerful muscle which, 
though not immediately attached to the penis, 
must exert, in all Marsupials, so important an 
influence upon its erection as to merit notice 
here. This is the external sphincter ani, or 
more properly ‘ sphincter cloace :’ it is an inch 
and a half in breadth in the Kangaroo and half 
an inch in thickness; from the back of the 
termination of the rectum it passes over the 
anal glands and sides of the base of the penis, 
inclosing the two bulbs with Cowper’s glands 
and their muscles, and terminates anteriorly in 
a strong fascia above the dorsum penis, so as 
to compress: against that part the vene dor- 
sales. 
This adjustment and function of the great 
sphincter did not escape the observation of 
Cowper. Speaking of the erectores penis of 
the Opossum, he says, “ the muscles of the 
cavernous bodies of the penis of this creature, 
having no connexion with the os pubis, cannot 
apply the dorsum penis to the last-named bone 
and compress the vein of the penis, whereby 
to retard the refluent blood and cause an erec- 
tion, as we have observed in other creatures ; 
but some large veins of the penis here take a 
different course, and pass through the middle 
parts of the bulb (crus), and are only liable to 
the compression made by the intumescence of 
the muscles (cc) that inclose them. But the 
chief agent in continuing the erection of the 
penis in this animal is the sphincter muscle of 
its anus, or rather cloaca; and not only the 
sphincter muscle of the cloaca of the male 
possum, but that of the female also, closely 
embraces the penis in coition, and effectually 
retards the refluent blood from its corpora caver- 
nosa, by compressing the veins of the penis.”* 
The penis is bent upon itself in a sigmoid 
form when retracted ; with the glans concealed 
just within the cloacal aperture, from which it 
emerges, as in the Ovipara, when the penis is 
turgid and erect. 
Female organs.—These consist of two ovaries, 
two oviducts or fallopian tubes, two uteri, two 
vagine, an uro-genital canal, a clitoris, mam- 
mary organs, and marsupial pouch. 
The ovaries are small and simple in the 
uniparous Kangaroos; tuberculate and rela- 
tively larger in the multiparous Opossums; 
but the largest size and most complicated 
form of these essential organs which I have 
met with in the Marsupial order were pre- 
sented by the Wombat (fig. 137). The 
* Phil. Trans. vol. xxiv. 1704, p. 1584, 
313 
ovaria are represented of their natural size in 
fig. 138, a a’, in the great Kangaroo, where they 
present an oval form and a smooth unbroken 
exterior, except after impregnation, when a 
large corpus luteum projects from the surface, 
as ata’. The ovaria are not inclosed by a cap- 
sular duplication of the peritoneum, but are 
lodged within the expanded orifice of the ovi- 
duct, or ‘pavilion,’ near the upper or anterior 
extremities of its two principal lobes or pro- 
cesses. These are of considerable extent, and 
their internal surface, which is highly vas- 
cular, is beset with ruge and papille. In 
the Dasyures and Petaurists the ovaries are 
elliptical, subcompressed, and smooth. In the 
Opossum the ovarium consists of a lax stroma 
remarkable for the number of ovisacs imbedded 
in it, the largest of which are the most super- 
ficial, and give rise to the tubercular projections 
on the surface of the ovary. 
In the Wombat (fig. 137) each ovary, be- 
sides being lodged in the pavilion, as in the 
Kangaroo, is inclosed with the pavilion in a 
Fig. 137. 
Ovarium and pavilion, Wombat. Natural size. 
eritoneal capsule. In the unimpregnated 
emale examined by me, the ovaries were six 
times as large as in the Kangaroo, and pre- 
sented a well-marked botryoidal form, resem- 
bling the ovarium of the bird. Numerous ovi- 
sacs in different stages of growth projected from 
the surface, the largest presenting a diameter of 
eight lines (fig. 137, a); the structure of these 
ovisacs, the character of the stroma in which they 
are imbedded, and the dense albugineous tunic 
by which they are inclosed, bespeak the strictly 
mammalian type of the ovaria of the Phascolo- 
mys as of every other genus of Marsupial; but 
the affinity of the Wombat to the Rodent order, 
in many species of which the ovaria are tu- 
