IN THE ORNITHORYNCHUS PARADOXUS. 151 
Memoir III. 
On the Kidneys, Urinary Bladder^ and Organs 
of Generation^ in the 3Iale of the Ornithoryn- 
chus paradoxus. 
The kidneys had suffered so much by long maceration 
in spirits, that they were reduced to a pulpy, homogeneous 
mass, which gave way under the smallest pressure. No- 
thing could be made of their internal structure. It is stated 
in the Anatomie Comparee, that the medullary portion of 
the kidneys in the Echidna terminates by four papilla, and 
that the pelvis of the kidney is confounded with the calices. 
Two ureters, very distinct in the Ornithorynchus, conduct 
the urine into a urinary bladder, thin in its parietes, but 
quite proportioned to the size of the animal. Air blown 
into the bladder by the blowpipe readily passed into the 
ureters, which I imagine to be rather a rare circumstance, 
as I do not remember to have found it so in any other ani- 
mal It is stated in the Anatomie Comparee^ that the in- 
sertion of the ureters is placed in all animals at a certain 
distance from the neck of the bladder, excepting in the 
Echidna and Ornithorynchus, in which this insertion takes 
place beyond a little swelling (hourrelet ), which seems to 
separate the bladder from the urethra, in such a way, that 
the ureters open into this latter canal, rather than into the 
bladder*; nevertheless, by inserting the blowpipe into 
® On slitting up the urinary bladder somewhat farther than is represented 
in the <jirawing, I do not find this to he borne out by tlie appeurance of the 
parts. 
