844 
ZOOLOGY. 
tinguish, besides the testes, long vasa deferentia, even a kind 
of vesiculse seminales, and a very considerable penis, with a 
hook-shaped glans. 
Each of the large ovaria of the female gryllus verrucivorus 
contains about fifty ova, disposed in bundles. The two 
organs are connected together at their posterior extremities, 
and open between the two sheaths of a part by which they 
are discharged from the body. 
In the silkworm moth, on the contrary, the ovarium re¬ 
sembles four rows of pearls; each row contains about sixty 
ova, which are laid from the end of the abdomen, alter pass¬ 
ing through a short duct, which has, however, connected 
with it several vesicular processes of uncertain use. 
The male organs of generation possess very different struc¬ 
tures in the different orders of fishes. 
In the torpedo there are manifest testicles, consisting partly 
of innumerable glandular and granular bodies, and partly of 
a substance like the soft roe of bony fishes. We find also 
vasa deferentia, and a vesicula seminalis, which opens into 
the rectum by means of a small papilla. 
The soft roe supplies the place of testes in the carp, and 
most other bony fishes. It lorms two elongated flat viscera 
of a white colour, and irregulartuberculated surface: placed 
at the sides of the intestines and swimming-bladder, so that 
the left encloses the rectum in a kind of groove. Through 
the middle of each soft roe passes a ductus deferens, which 
opens behind into a kind of vesicula seminalis, and this ter¬ 
minates in the cloaca. It is a curious circumstance that 
hermaphrodites, possessing the complete organs of both sexes, 
are found frequently in this species. 
In the female torpedo there are two uteri, communicating 
with the cloaca by means of a common vagina. The ovi¬ 
ducts form one infundibulum, which receives the ova as they 
successively arrive at maturity. These are very large in com¬ 
parison with those of the bony fishes. The yolk, in its pas¬ 
sage through the oviduct, acquires its albumen and shell. 
The latter is of a horny consistence, and is known by the 
name of the sea-mouse. It has an elongated quadrangular 
figure, and its four corners are curved and pointed in the 
skate, while they form horny plaited eminences in the sharks. 
The secretion of the albumen, and the formation of the shell 
are performed by the papillous internal surface of the duct; 
and chiefly by two glandular swellings which appear to¬ 
wards its anterior extremity in the summer months while the 
eggs are being laid. 
The structure is much more simple in the carp, and pro¬ 
bably also in the other oviparous bony fishes. The two roes 
occupy the same position as the soft roe of the male does. 
They are placed at the side of the intestines, liver, and swim¬ 
ming bladder, as far as the anus. They consist of a delicate 
membrane inclosing the ova, which are all of one size, and 
extremely numerous (more than 200,000 in the carp); and 
terminate by a common opening behind the anus. 
The kidney, testes, and epididymis, lie close together in 
the testudines, but each of the three organs may be distin¬ 
guished, by its peculiar colour and structure, on the first view. 
They have no vesiculse seminales, according to Blumenbach, 
though Lieberkuhn speaks of them. The penis is very large, 
and retracted within the cloaca in its ordinary state. Instead 
of an urethra, this part contains a groove, whose margins 
approach to each other, when the part is erected, so as to form 
a closed canal. This may be compared with the groove¬ 
like continuation of the oesophagus, which goes into the third 
stomach of ruminating animals. The glans terminates in an 
obtuse hook-like point, somewhat resembling the end of the 
elephant’s trunk. 
Frogs have large vesiculoe seminales, and a small papilla 
in the cloaca instead of a penis. Both these parts are want¬ 
ing in the toad. 
Crocodiles have a simple penis, while lizards have two; 
and the water-newt, which does not copulate, has no organ 
of the kind. 
Serpents have long slender testicles, no vesiculae seminales, 
but a double penis, each of which has a bifid point covered 
with sharp papillae. 
The tortoise has amanifest clitoris, lying in the cloaca. The 
oviducts are double, and have two openings into the cloaca. 
Frogs have two long convoluted oviducts which arise by 
open orifices at the sides of the heart. The ovaria lie under 
the liver, so that it is difficult to conceive how the ova o- e t 
into the above-mentioned openings. These oviducts form a 
large and thick-sided protuberance, which Blumenbach calls, 
improperly, a uterus. The uterus opens into the cloaca. 
The toads have not this large uterus; but their oviducts 
terminate by a common tube in the cloaca. 
Lizards have on the whole a similar structure to that of the 
last-mentioned animals, and the ovaria contain fewer ova 
and serpents also. The serpents have double external 
openings of the genitals for the reception of the double 
organs of the male. 
The testes, which lie near the kidneys, and the ductus 
deferentes, are the only male organs which are constantly 
found in the whole class of birds. In a very few instances 
as in the cock, the last mentioned canals terminate in a 
dilated part, which has been considered analogous to the 
vesiculse seminales. Instead of a penis, most birds have 
in the cloaca two small papilla, on which the seminal 
ducts terminate. But some have a simple penis of con¬ 
siderable length, which is ordinarily concealed and re¬ 
tracted within the cloaca; but remains visible externally 
for some time after copulation. It forms a long worm-shaped 
tube in the drake, and constitutes a groove in the ostrich, 
which is visible when the animal discharges its urine. 
The female organs of generation in birds, may be most 
conveniently arranged under three divisions; the external 
parts including the cloaca; the tubus genitalis (which an¬ 
swers to the Fallopian tube of the mammalia or oviduct,) 
resembling an intestine ; and, lastly, the ovarium, which is 
almost entirely separate irom the latter part. 
As the general structure of these parts is very uniform in 
all birds, we may take as an example the most familiarly 
known species, the hen. 
The external opening of the genitals consists of a trans¬ 
verse slit behind the ossa pubis, which do not form a sym¬ 
physis ; this is larger in the hen than in the cock; and its 
smaller anterior labium is covered by the larger posterior one 
(velabrum). 
This slit leads to the cloaca, in which several organs open. 
These are the rectum; the two ureters on the prominent 
margin of that part; the vagina on the left; behind which, 
and on the upper part of the cloaca, there is the bursa 
Fubricii. 
A scrotum, or bag, in which the testes hang on the out¬ 
side of the abdominal cavity, exists only in the mammalia ; 
but is not by any means common to afl the genera. It is 
not found in the aquatic animals of this class, nor in those 
which live under ground, as the mole; nor in such as roll 
themselves up on the approach of danger, as the hedgehoo. 
Some mammalia, again, have the power of withdrawing 
these glands from the abdomen, and retracting them into the 
cavity according to circumstances; as the guinea-pig, the 
squirrel, the rat, the hamster, (marmota cricetus) and Ca¬ 
nadian musk-rat (mils zibethicus). 
A scrotum exists in all the quadrumana and in most of the 
carnivora; in animals of the opossum kind, which have it 
in front of the pelvis; in the hare and geiboa; in most of 
the ruminating genera, and in the solidungula. 
The testes are placed under the skin of the perineum in the 
pachydermata and the civet; or under that of the groin, as 
in the camel and otter. They pass from the abdomen into 
one or the other of these situations, particularly at the rutting 
season, in the bats, the mole, shrew, and hedgehog; and in 
several rodenlia, as the rat, guinea-pig, porcupine, beaver, 
squirrel, &c. They remain constantly in the abdomen in 
the ornithorhynchus paradoxus and hystrix, in the elephant, 
hyrax, the amphibious mammalia, and the cetacea. 
The tunica vaginalis exists constantly in the mammalia, 
and the cavity of this covering always communicates by 
means of a narrow canal, with the abdomen. 
In several quadrupeds, as the dog , horse, ram, and others, 
thera 
