ZOOLOGY. 
845 
there is a body composed of condensed cellular substance, 
lying according to the axis of the testicle near the epididymis, 
and known by the name of corpus Highmori. 
The vasa deferentia are usually enlarged in size, and as¬ 
sume a cellular structure for some short distance previous to 
their termination. The structure of this part is particularly 
remarkable in the horse. 
Most species of mammalia, (and, with the exception of the 
cetacea, some out of every other order in the class,) possess 
vesiculae seminales. The vesiculae seminales swell to a vast 
size in the rutting season in many animals, as in some of the 
simiae, and most particularly in the hedgehog. 
The following animals have no vesiculae seminales, ac¬ 
cording to Cuvier: the plantigrada, except the racoon and 
hedgehog; all the carnivora and marsupial animals; the 
ru'mihantia, the seals, the cetacea, and the two species of 
ornithorhynchus. Their existence or absence does not seem 
to follow any general law. 
In the hedgehog these parts are of a vast size, much ex¬ 
ceeding the volume of the testes. The rodentia are generally 
distinguished by the great size of their vesicles. These parts 
in the guinea-pig are long, uniform, cylindrical cavities, con¬ 
taining generally a firm cheesy matter. In the boar they are 
very large, and of a lobulated structure; a common excre¬ 
tory duct receives the branches from the lobes. In the horse 
they form two large and simple membranous bags, opening 
near the vasa deferentia, but separately. 
The possession of a prostate (in some instances simple, but 
generally divided into two parts) is peculiar to the mammalia, 
and seems to take place in every species of the whole class. 
In many species the penis consists of a single corpus ca- 
vernosum, without any septum. The pig and the cetacea 
furnish examples of this structure ; and in the latter animals 
there are numerous tendinous layers crossing it. 
In some species, where the act of copulation requires a 
longer portion of time, as in the dog, badger, &c. the corpus 
spongiosum of the glans, and of the posterior part of the 
penis, swells during the act much more considerably than the 
rest of the organ, and thus the male and female are held to¬ 
gether during a sufficient space of time for the discharge of 
the seminal fluid. 
In the quadrumana and bats the penis hangs loose from the 
pubis as in man. In most of the other mammalia it is con¬ 
tained in a sheath of the integuments, which extends nearly to 
the navel. This sheath has an adductor and a retractor muscle. 
The penis is generally folded when drawn within the sheath, 
on account of its length. In some animals it turns back when 
it has reached the front of the pubis, and passes out near the 
anus; this is the case with the guinea-pig, marmot, and squir¬ 
rel. It goes directly backwards from the beginning in the 
bare, rat, dormouse, and opossum, where the prepuce is found 
close to the anus. 
The corpora cavernosa form a cylindrical ring in the kan¬ 
garoo, and the urethra passes in the centre. 
Several species of mammalia possess a peculiar bone in the 
penis, generally of a cylindrical form, but sometimes grooved. 
This is the case with some of the simiae, most of the bat-kind, 
the hamster, and several others of the mouse-kind, the dog, 
bear, badger, weasel, seal, walrus, &c. It is somewhat re¬ 
markable this bone should not be found in all the species of 
the same genus. 
In most of the male animals of this class the urethra runs 
on to the end of the glans, and forms a common passage for 
the urine, prostatic liquor, and semen. In some few species, 
the passage which conducts the two former fluids, is distinct 
from that of the seminal liquor. The bifid fork-like glans of 
the opossum has three openings, one at the point of bifurca¬ 
tion for transmitting the urine; and two for the seminal fluid 
at the two extremities of the glans. The short urethra of the 
ornithorhynchus paradoxus opens directly into the cloaca, 
and the large penis of the animal serves merely to conduct 
the seminal fluid. It divides into two parts at its extremity, 
and each of these is furnished with sharp papillae, which are 
perforated for the passage of the semen. A similar structure 
Vol. XXIV. No. 1677. 
obtains in the ornithorhynchus hystrix, where the penis 
divides into four glandes. 
In some species of the cat-kind the glans is covered with 
retroverted papillae, which may enable the male to hold the 
female longer in his embraces. Horny pointed processes 
turned backwards are found in the penis of the savia paca. 
Lastly, it deserves to be mentioned, that in some species 
of this class, the male penis, while unerected, is turned back¬ 
wards, so that the urine is voided in the male in the same 
direction as in the female. The hare, lion, and camel, afford 
instances of this structure. But these retromingents do not 
copulate backwards. 
The clitoris probably is wanting in no other instance in 
the mammalia than the ornithorhynchus. It contains a small 
bone in several species of mammalia, as the marmota citillus, 
the 'racoon, (ursus lotor) the lioness, the sea-otter, &c , and 
in the opossum it possesses a bifid glans, like that of the penis. 
In consequence of the horizontal position of the body of 
quadrupeds, the clitoris is at the under-margin of the orifice 
of the vagina, instead of the upper one, as in women. 
Blumenbach says, “ a true hymen, or one at least, which 
in form and situation resembles that of the human subject, 
has been observed in no other animal.” But according to 
Cuvier, the mare and ass, and some of the simise, have an 
analogous structure. Hence he concludes, that the hymen is 
not a part exclusively peculiar to the human species. 
The vagina of quadrupeds is distinguished from that of the 
human subject by two chief characters: its direction, which 
corresponds with the axis of the uterus, and the structure of 
its internal surface, which is little villous. 
Dr. Gartner, of Copenhagen, has recently called the atten¬ 
tion of anatomists to the existence of two canals in the vagina 
and uterus of the cow, and some other mammalia. These 
canals commence in the neighbourhood of the Fallopian 
tubes, and open into the vagina near the meatus urinarius. 
The structure and form of the uterus vary very considerably 
in this class. In no instance does it possess that thickness, 
nor has its parenchyma that density and toughness which are 
observed in the human female. 
The variations in form of the impregnated uterus are re¬ 
duced by Blumenbach to the following heads: 
]. The simple uterus without horns (uterus simplex) which 
is generally of a pyramidal or oval figure. This is exempli¬ 
fied in those animals where we have stated that it possesses 
thick coats. Its circumference in some simiae presents a more 
triangular form than in the woman: and towards the upper 
part, in the neighbourhood of the Fallopian tubes, there is an 
obscure division into two blind sacs (as in the gibbon, or 
long-armed ape); this distinction is more strongly expressed 
in the lori, (lemur tardigradus) so as to form a manifest ap¬ 
proach to the uterus bicornis. 
2. A simple uterus with straight or convoluted horns (ute¬ 
rus bicornis). They are straight in the bitch, in the racoon, 
in the bats of this country, (Germany) in the sea-otter, seal, 
&c., somewhat convoluted in the cetacea, mare, and hedge¬ 
hog, and still more tortuous in the bisulca. 
3. A double uterus, having the appearance of two horns, 
which open separately into the vagina; this is seen in the 
hare, mole, and rabbit (uterus duplex). 
4. A double uterus, with extraordinary lateral convolu¬ 
tions, is met with in the opossum and kangaroo (uterus an- 
fractuosus). 1 
These various forms undergo different changes in the preg¬ 
nant stale. 
The alteration in the simple uterus is, on the whole, analo¬ 
gous to that which occurs in the human female. 
The pregnant uterus 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 ot the mare is con¬ 
fined in its situation to the proper uterus. In the cow it ex¬ 
tends at the same time into one of the horns, which is en¬ 
larged for its reception. In those, on the contrary, which 
bring forth many young at once,,as also in the double ute¬ 
rus of.the hare and rabbit, both cornua are divided by con- 
9 D traded 
