COMPARATIVE ANATOMY. 
Hteri, and, at least for some extent, a 
double vagina. 
Ovaria are found in the females of all 
animals where the male possesses testicles : 
but their structure is in general more sim- 
ple than that of the latter glands, particu- 
larly in the first class. These bodies were 
formerly called the female testicles; but 
the term ovary is much preferable, as it de- 
notes the function which the parts perform 
in the animal economy. For, if the office 
of these bodies be at all dubious, when 
their structure is considered in man and 
most of the mammalia ; their organization 
is so evident in the other classes, that no 
doubt can be entertained respecting their 
physiology. It is manifest in all these, 
that the ovaria serve for the growth and 
preservation of the germs or ova, which 
exist in these bodies, completely formed 
before the act of copulation. Analogy 
leads us to conclude that these bodies 
have the same office in the mammalia ; and 
thus our explanation and illustration of this 
most interesting part of physiology, are 
entirely derived from researches in com- 
parative anatomy. 
Of all the external female sexual organs 
in tlie mammalia, the clitoris is found the 
most universally and invariably. It exists 
even in the whales, and probably is want- 
ing in no other instance than the ornithor- 
hynclms. As its general structure much 
resembles that of the male penis, it con- 
tains a small bone in several specie.s, as 
the marmota citillus, the racoon, lioness, 
and sea-otter. 
A true hymep, or one at least, which in 
form and situation resembles that of the 
human subject, has been observed in no 
other animal. 
The structure and form of the uterus 
vary very considerably in the mammalia. 
In no instance does it possess that thick- 
ness, nor has its parenchyma that density 
and toughness, which are observed in the 
human female. Of those which I have dis- 
sected, the simia sylvanus had compara- 
tively the firmest uterus. The two-toed 
ant-eater came the next in order in this 
respect. But in the greater number of 
mammalia, this organ is thin in its coats, 
resembling an intestine in appearance, and 
provided with a true muscidar covering. 
The variations in the form of the unim- 
pregnated uterus may be reduced to the 
following heads : 
1. The sfinple uterus without horns, 
(uterus simplex,) which is generally of a 
pyramidal or oval figure. This is exem* 
plified in those animals, where we have 
stated that it possesses thick coats. Its 
circumference in some simioe presents a 
more triangular form than in the woman ; 
and towards the upper part, in the neigh- 
bourhood of the Fallopian tubes, there is 
an obscure division into two blind sacs, (as 
in the gibbon, or long-armed ape) : tJiis 
distinction is more strongly expressed iu 
the lori, (lemur tardigradus,) so as to form 
a manifest approach to the uterus bicornis. 
a. A simple uterus with straight or con- 
voluted horns (uterus bicornis.) They 
are straight in the bitch, in the bats of this 
country, in the sea-otter, seal, &c. ; some- 
what convoluted in the cetacea, mare, and 
hedge-hog, and still more tortuous in the. 
bisulca. 
3. A double uterus, having the appear- 
ance of two horns, which open separately 
into the vagina : this is seen in the hare 
and rabbit, (uterus duplex.) 
4. A double uterus, with extraordinary 
lateral convolutions, is met with in the 
opossoin and kanguroo, (uterus anfrac- 
tuosus.) 
These various forms undergo different 
changes in the pregnant state. 
The alteration in the simple uterus is, on 
the whole, analogous to that which occurs 
in the human female. 
The pregnant utenis bicornis suffers a 
different change in those animals which 
bear only one at a time, from that which 
it undergoes in the multipara. The foetus 
of the mare is confined in its situation to 
the proper uterus. In the cow it extends 
at the same time into one of the horns, 
which is enlarged for its reception. In 
those, on the contrary, which bring forth 
many young at once, as also in the double 
uterus of the hare and rabbit, both cornua 
are divided by contracted portions into a 
number of pouches corresponding to that 
of the young ; and where those horns are 
straight in the unimpreguated state, as in 
the bitch, they become convoluted. 
The uterus of the opossum and kanguroo 
suffers tlie least change from its usual ap- 
pearance in the impregnated state. For 
-these strange animals bring their young 
into the world so disproportionately small, 
that they appear like early abortions. 
The passage of the foetus, in the opos- 
sum tribe and the kanguroo, from the ca- 
vity of the uterus into the false belly, 
where it adheres by its mouth to the nip- 
ple, presents one of the most singular ami 
