Volltext: The Cyclopaedia of Anatomy and Physiology, vol. 2: Dia-Ins (2)

the gut, as it descends, gradually enlarging, to 
the lower part of the intestine, where it sud¬ 
denly contracts and runs down, as a very slender 
canal, to near the vulva. It is partly covered 
by two long slender bodies of a horny sub¬ 
stance, representing a bifurcate penis. 
From this comparison of different genera 
of the Nematoidea, it is seen that, although 
there are many varieties of structure in the 
efferent and copulative part of the male gene¬ 
rative apparatus, the essential or secerning por¬ 
tion uniformly consists of a single tube. A 
like uniformity of structure does not obtain in 
the essential parts of the female organs : in a 
few instances the ovary is single, correspond¬ 
ing to the testis in the male, but in the greater 
number of the Nematoid worms it consists of 
two filamentary tubes. 
The Strongylus gigas is an example of the 
more simple structure above alluded to. The 
single ovary commences by an obtuse blind 
extremity close to the anal extremity of the 
body, and is firmly attached to the termination 
of the intestine ; it passes first in a straight line 
towards the anterior extremity of the body, 
and when arrived to within a short distance 
from the vulva, is again 
Fig. 95. attached to the parietes 
of the body, and makes 
a sudden turn back¬ 
wards (fjfig. 95); it 
then forms two long 
loops about the mid¬ 
dle of the body and 
returns again forwards, 
suddenly dilating into 
an uterus (e), which is 
three inches in length, 
and from the anterior 
extremity of which 
a slender cylindrical 
tube, or vagina, about 
an inch in length, (e,d, 
fig. 95) is continued, 
which after forming a 
small convolution ter¬ 
minates in the vulva, 
at the distance of two 
inches from the ante¬ 
rior extremity of the 
body. Eudolphi was 
uncertain as to the ter¬ 
mination of the ovi¬ 
duct in the Strongylus 
gigas, and Professor 
Otto, who appears to 
have mistaken its blind 
commencement for its 
termination, believed 
that the oviduct opened 
into the rectum. 
The theory which 
had suggested itself to 
Eudolphi of the corre- 
_ lation of a simple ovi- 
Anterior extremity of the duct in the female with 
Strongylus gigas, showing t} piculum simplex 
the commencement of the r , * r 
digestive and the termina- °* *he male, and of a 
tion of the generative tube, double oviduct with 
the spiculum duplex, receives additional dis¬ 
proof from the circumstance of the uteri and 
oviducts being double in the Strongylus in- 
flexus and Strongylus armatus. In the former 
species (which infests the bronchial tubes and 
pulmonary vessels of the Porpesse, and which 
I once found in the right ventricle of the heart 
of that animal,) each of the two female tubular 
organs may be divided into ovary, oviduct, 
and uterus : the ovary is one inch in length, 
commences by a point opposite the middle 
of the body, and, after slightly enlarging, 
abruptly contracts into a capillary duct about 
two lines in length, which may be termed the 
oviduct, or Fallopian tube, and this opens 
into a dilated moniliform uterus three inches 
in length ; the divisions here described were 
constant in several individuals examined, and 
cannot, therefore, be considered to result from 
partial contractions. Both tubes are remark¬ 
ably short, presenting none of the convolutions 
characteristic of the oviducts of Ascaris and 
Filaria, but extend, in a straight line, (with 
the exception of the short twisted capillary 
communication between the ovaria and uteri,) 
to the vulva, which forms a slight projec¬ 
tion below the curved anal extremity of the 
The reason of this situation of the vulva 
seems to be the fixed condition of the head 
of this species of Strongylus. In both sexes 
it is commonly imbedded so tightly in a con¬ 
densed portion of the periphery of the lung as 
to be with difficulty extracted ; the anal extre¬ 
mity, on the contrary, hangs freely in the 
larger branches of the bronchi, where the 
coitus, in consequence of the above dispo¬ 
sition of the female organs, may readily take 
In the Strongylus armatus the two oviducts 
terminate in a single dilated uterus, and the 
vulva is situated at the anterior extremity of 
the body, close to the mouth. 
We find a similar situation of the vulva in 
a species of Filaria, about thirty inches in 
length, which infests the abdominal cavity of 
the Rhea, or American Ostrich. The single 
portion of the genital tube continued from the 
vulva is one inch and a quarter in length ; 
it then divides, and the two oviducts, after 
forming several interlaced convolutions in the 
middle third of the body, separate ; one ex¬ 
tends to the anal, the other to the oral ex¬ 
tremities of the body, where the capillary 
portions of the oviducts respectively com¬ 
In the Ascaris Lumbricoides the female organs 
(fig. 96) consist of a vulva, a vagina, a uterus, 
which divides into two long tortuous oviducts 
gradually diminishing to a capillary tube, 
which may be regarded as ovaries. All these 
parts are remarkable in the recent animal 
for their extreme whiteness. The vulva (d, 
fig. 72,) is situated on the ventral surface of 
the body at the junction of the anterior and 
middle thirds of the body, which is generally 
marked at that part by a slight constriction. 
The vagina is a slightly wavy canal five or six 
lines in length, which passes beneath the in-


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