238 MR. G. BENNETT ON THE HISTORY AND HABITS OF 
was afterwards confirmed by facts,) that as the gestation advances, the gland becomes 
enlarged ; and that when the lacteal secretion is no longer required for the support of 
the young, it again decreases, becoming scarcely perceptible. 
Omitting the rest of the anatomy, I shall at once proceed to the result of the inves- 
tigation of the uterine organs. These I found to consist of two uteri extending some 
distance above the pelvis. On the upper, rather posterior and lateral part of the uteri 
(but more particularly and more clearly marked in the left than in the right wterus,) were 
well developed clusters of ova, giving an indication of an impregnated female. Both 
uteri, gradually diminishing in size as they proceeded, had their termination in the 
cloaca; the bladder was situated between and rather anterior to the wteri, and the rectum 
posterior to the bladder ; and both these organs also had their termination in the cloaca. 
The ovaries were white!, and covered by a semitransparent membrane, through which 
the ova could be readily distinguished. The left uterus had the largest development : 
its coats were thickened, and on laying the internal part open gradually from the os 
uteri to the apex, three loose ova of the size of swan-shot were successively exposed to 
view, one a short distance above the other, but all in the uterine cavity. T hey were 
perfectly white and quite round; their external coat consisted of a dense opake mem- 
brane ; and they could be taken into the hand and examined without fear of their sus- 
taining any injury®. 
The os uteri was contracted so closely at this period as scarcely to permit a very thin 
' After having been preserved in spirits, they became rather of a yellowish colour : indeed the whole of the 
preparation of the uterine organs had, as may be supposed, a far more beautiful appearance when viewed in 
the recent state than after it had been for some time preserved in spirit. For such purposes I should prefer 
brine to spirit, as the natural appearance of animal preparations is not so liable to be lost. 
* I took the earliest opportunity of transmitting to my friend Mr. Owen the impregnated uterus of this Or- 
nithorhynchus, and of two others which I subsequently obtained, and the following is the result of his exami- 
nation of these specimens as detailed in a paper just published by him in the ‘ Philosophical Transactions.’ 
“In each of the specimens, the left ovary only had taken on the sexual actions, but did not exceed in size the 
same parts in the unimpregnated specimens above described. The right ovary had, however, become enlarged ; 
it measured half an inch in length, a third of an inch in breadth, and was about half a line in thickness: a few 
ovisacs, about the size of a small pin’s head, projected from the surface. 
“The left ovary in each of the specimens was concealed by the thin membrane forming the expanded orifice of 
the oviduct. In one of these it was with some difficulty it could be withdrawn from the Fallopian aperture, owing 
to the adhesion which was occasioned by what appeared to be a coagulated secretion; a circumstance which 
must have effectually ensured the passage of the ovum into the oviduct. In two of the specimens, the left ovary 
presented two empty ovisacs, or corpora lutea, corresponding with the number of ova found in the wterus. In 
the third specimen, the left ovary presented two ovisacs still uncicatrized, but only one ovum was contained in 
the uterus. * * * * 
“The discharged ovisacs were of an elongated flask-shaped form, about three lines in length and two in 
diameter, with the margins of the orifice through which the ovum and granular substance had passed everted, 
with a slight contraction, resembling the neck of a flask, below the aperture. On compressing these ovisacs, 
small portions of coagulated substance escaped. When longitudinally divided, they were found to consist of 
the same parts as the ovisac before impregnation, with the exception of the granular contents and granular 
a 
