COMPARATIVE ANATOMY. 
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 obtains in the ornitho- 
rhynchus hystrix, where the penis divides 
into four glandes. 
In some species of the cat-kind the 
glans is covered with retroverted papill®, 
which, as these animals have no vesicul® 
seminales, may enable the male to hold the 
female longer in his embraces. 
Lastly, it deserves to be mentioned, that 
in some mammalia, the male penis, while 
unerected, is turned backwards ; so that the, 
urine is voided in the male in the same di- 
rection as in the female. The hare, lion, 
and camel, afford instances of this struc- 
ture. But the statement which has been so 
often repeated since tlie time of Aristotle, 
that these retromingentia copulate back- 
wards, is erroneous. 
BIRDS. 
The testes, which lie near the kidnies, 
and the ductus deferentes, are the only 
male orgdns which are constantly found in 
the whole class. 
In a very few instances, as in the cock, 
the last mentioned canals terminate in a di- 
lated part, which has been considered ana- 
logous to the vesicul® seminales. Instead 
of a penis, most birds have in the cloaca 
two small papill®, on which the seminal 
ducts terminate. This is the case in the 
cock, turkey, and pigeon. 
Some few species have a simple penis of 
considerable length, which is ordinarily con- 
cealed and retracted 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. 
AMPHIBIA. 
The kidney, testes, and epididymis, lie 
close togetlier in the testudines ; but each 
of the three organs may be distinguished 
by its peculiar colour and structure on the 
first view. They 'appear to have no vesi- 
pul® seminales; none at least could be dis- 
covered in a testudo gimca, which was lately 
dissected. The penis on the contrary is very 
large ; and retracted within the cloaca in 
its ordinary state. Instead of an urethi-a, 
this part contains a groove, whose margins 
approach to each other, when the part is 
etected, so as to form a closed canal. The 
glans terminates in an obtuse hook-like 
point, somewhat resembling the end of the 
elephant’s trunk. 
Serpents have long slender testicles ; no 
vesicul® seminales ; but a double penis, 
each of which has a bifid point covered 
with sharp papill®. 
FISHES. 
The male organs of generation possess 
very different structures in the different or- 
ders of this class. We shall take two spe- 
cies as examples ; the torpedo for the 
cartilaginous, and the carp for the bony 
fishes. 
In the former instance 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 vesicida 
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 
forms two elongated flat viscera of a white 
colour, and irregular tuberculated 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 eacli soft roe passes a ductus 
deferens, which opens behind into a kind of 
vesicula seminalis, and this terminates in the 
cloaca. 
FEMALE ORGANS OF GENERATION. 
An ovarium is the most essential and uni- 
versal of all the female parts of generation. 
In addition to this, those animals which 
brerathe by means of lungs, as well as some 
fishes, and several white-blooded animals, 
have also oviducts, (Fallopian tubes, &c.) 
or canals leading from the ovarium to the 
uterus : and lastly, those, at least, which 
are impregnated by a real copulation, 
possess a vagina, or canal connecting the 
uterus to the external organs of generation. 
In birds all the parts which we have just 
mentioned are single. Some cartilaginous 
fishes have two oviducts; beginning, how- 
ever, by a common opening, and termi- 
nating in a simple uterus. The human fe- 
male, as well as that of many other mam- 
malia, has two ovaria, with an oviduct be- 
longing to each; a simple uterus and va- 
gina. The females of this class in several 
other instances, possess an uterus bicornis ; 
and in some cases the generative organs are 
double throughout; that is, there arel;we 
