CONTRIBUTIONS TO ZOOLOGICAL PATHOLOGY. 35 
of the posterior aorta, situated around the origin of the coeliac 
axis, into the abdominal cavity. The interior of this cavity was 
almost completely filled with coagulated blood; and on searching 
carefully for the aperture in the aorta whence the discharge had 
come, two entozoa were found entangled in the coagulum, between 
two folds of the jejunum at the root of the mesentery. The aorta 
was then cut through at the aonic aperture in the diaphragm, and 
the trunk carefully separated as far as its bifurcation into its iliac 
branches : the whole was removed for further dissection. The 
following were its pathological conditions : — 
The tumour was of a large size, occupying the entire lower half 
of the periphery of the aorta. It was situated around the roots of 
the coeliac axis, extending anteriorly between the crura of the 
diaphragm, and posteriorly involving the origin of the anterior 
mesenteric artery ; and along its right side, between the roots of 
the hepatic and anterior mesenteric arteries, an oblique lacerated 
fissure was found, penetrating through the parietes of the tumour, 
but having its space almost entirely filled up by the protrusion of 
two entozoa. 
The interior of the tumour contained an irregular clot of fibrin 
arranged in layers ; and, on separation of these, seven entozoa were 
found between them. These worms were not embedded in any 
cysts with distinct walls, but were simply lying in small irregular 
cavities between the layers, and between which cysts and the 
general cavity of the tumour there existed a communication in only 
one instance. In the margin of the fibrinous clot, close to the 
aperture through the coats of the artery, another space of a larger 
size was observed. This space was still partly occupied by the 
bodies of those entozoa that were engaged in the aperture, and it 
w'as evident that this space between the layers of the fibrin had 
also been formerly entirely occupied by them. These entozoa 
were engaged in the aperture irregularly ; in one the head was 
entirely protruded, and the other had its body doubled up. 
The coats of the artery that entered into the formation of the 
tumour were not increased in thickness, and towards the aperture 
they became gradually thinned. Here and there the inner surface 
of the tumour was studded with small tubercular elevations, in the 
centre of the larger of which the rudimentary and embryonic forms 
of the entozoa were found ; and on the margin of a fissure one of 
a considerable size was found, embedded on the inner surface of 
the middle coat of the artery, and which, from the change induced 
on the elasticity of the artery by its presence, had evidently been 
the immediate cause of the sudden rupture of all its coats. 
The entozoa that were found in the abdominal cavity, as also 
