394 
The ovaria correspond in situation and sur- 
rounding attachments with the testes in the 
male; and the oviducts and uteri exhibit in 
their closely convoluted disposition an analogy 
with the long epididymis or vas deferens. 
The left ovary (fig.191, f) is an irregular, 
semi-elliptical, flattened body, with a wrinkled 
and slightly granulated surface in the unexcited 
state; but thicker, and with the surface studded 
by elevations formed by the ovisacs in different 
stages of development at the season of sexual 
excitement. At this period I have usually 
found two ovisacs, as in the figure, which are 
conspicuously larger than the rest, and present- 
ing each a diameter of about two lines. The 
right ovary (/”) is a narrow, thin, generally 
elongated y; sometimes broader, with a 
finely granulated surface. It is often scarcely 
to be distinguished from the ovarian ligament 
to which it is attached. This ligament (i, 2) 
arises from the posterior parietes of the abdo- 
men, behind and a little on the outer side of 
the kidney, and passes along the edge of the 
broad ligament to the fallopian extremity of the 
oviduct, where it divides into two; one portion 
is attached to the side of the ovary, the other to 
the posterior margin of the fallopian orifice: 
after a course of an inch they again unite, and 
the ligament is continued along the anterior 
part of the uterus to its cervix, where it is in- 
sensibly lost. The two separated portions of 
the ligament support a large pouch of perito- 
neum which forms the ovarian capsule; the 
wide anterior orifice of the oviduct is also, by 
means of this ligament, prevented from being 
drawn away from the ovary. 
The efferent tube of the ovarian products is 
present on both sides of the body, and is divi- 
sible into an oviduct, or fallopian tube, (d’,) 
and an uterus (d). The size of the latter is 
nearly equal on both sides, but the right ovi- 
duct is much shorter than the left, and corre- 
sponds with the abortive condition of the ovary. 
e external serous coat of the oviduct is 
loosely connected to the muscular coat by fila- 
mentary processes of cellular membrane, among 
which numerous tortuous vessels ramify. The 
muscular coat is thin and compact, and is most 
readily demonstrable in the uterus. The mu- 
cous coat is thin and smooth in the oviduct; 
it is thick, soft, plicated, but not villous, in 
the uterus. 
The left uterus in a female with a large 
ovary, shot in the month of September, was two 
inches long, from four to five lines in diameter, 
and about a line thick in its parietes ; it be- 
came suddenly contracted and thinner in its 
coats to form the oviduct, which presented a 
diameter of about two lines, slightly enlarging 
to within an inch of the extremity, which forms 
a wide membranous pouch, (d”,) opening into 
the capsule of the ovary by an oblong orifice or 
slit (e) of eight lines in extent. The edges of 
this orifice were entire,as in the oviducts of 
Reptiles, not indented as in the fimbriated ex- 
tremity of the Fallopian tube in ordinary qua- 
drupeds. The entire length of the oviduct 
and uterine tube, when detached from their con- 
nections with the mesometry, was nine inches. 
MONOTREMATA. 
The right uterus and oviduct of the same speci- 
men exhibited similar differences in diameter 
and structure, but was shorter, measuring only 
six inches in length. oi) 
In a specimen with a slightly developed 
ovary, killed by Mr. Bell in April, the uteri 
were not much wider than the oviducts, and not 
thicker in their coats; the entire tubes were 
much less in all their dimensions than those 
just described. 
In the specimen above described with the 
large ovary, the thickened parietes of the first — 
portion of the uterine tube depended chiefly on 
an increase of the inner membrane, which pre- 
sents in a high degree the character of a se- 
creting surface. This membrane at the cervix 
uteri presented in all the specimens many 
deep and close-set furrows, which, as the 
grew wider, were gradually lost, and the surface 
became more or less smooth in the different 
specimens, being most irregular in the i 
men with the largest ovary. In the oviduct, 
the inner surface is at first smooth after leaving 
the uterus, but beyond that becomes finely re- 
ticulate, and in the terminal dilated part be- 
comes again smooth. The cervix uteri makes 
a valvular projection analogous to an os tince 
on each side of the commencement of the uro- 
genital canal, just beyond the orifice of the 
urinary bladder. There are two orifices on 
each of these prominences; the lower one is the 
termination of the ureter, and a bristle is repre- 
sented as passing through it in fig. 191; the 
upper or anterior orifice is the os uteri, m. 
n young or virgin Ornithorhynchi this ori- 
fice forms scarcely any projection into the aro- 
genital canal, and it is divided by a narrow 
septum, or hymen.* a 
“The uro-genital canal ©) is one inch anda 
half long, and three or four lines in diameter, 
but capable of being dilated to as great an 
extent probably as the pelvis will admit of; 
the diameter of the bony passage being seven- 
tenths of an inch. It is invested with a mus-— 
cular coat, the external fibres of which are 
longitudinal, the internal circular. The inner — 
membrane of this part is disposed in longi- 
tudinal ruge more or less marked, but pre- 
sents as little the character of a secreting mem=- 
brane as that of the vestibule, being smooth 
and shining; the orifices of a few minute 
follicles are situated in the interstices of the 
ruge near the orifice of the urinary bladder. 
It is this division only of the rom 
the uterus which is situated within the pelvis, 
the vestibule being produced beyond it, a 
the common outlet being in consequence sit 
ated at a considerable distance from the @ 
of the pelvis.t 
If the Ornithorhynchus were oviparous, its 
eggs must be disproportionately small compared 
with those of birds, in order to pass through — 
the unyielding pelvis, unless the albumen and — 
shell were subsequently added to the yolk in 
sate TO 
4 
Ls AD 
a , . 
el ee 
+t In this structure, as well as in its aquatic life, 
the Ornithorhynchus resembles the Beaver. ‘ 
