96 Dr. Davy on the urinary organs and urine 
the spine ; comparatively pretty large; very much lobulated ; 
of a bright red colour, and rather tender. 
The ureters do not terminate in the bladder, but in the 
rectum, by two soft papillae projecting a little, and situated 
between the orifice of the bladder and the anus, nearer the 
former than the latter. 
The bladder of urine is of large dimensions ; nearly glo- 
bular ; semi-transparent, and yet pretty strong and contractile. 
It opens into the rectum, a few lines behind the anus, by a 
large orifice, very well adapted to receive the urine, as it flows 
from the ureters, when the anus is closed, as it usually is, by 
its powerful sphincter muscle. 
The urinary organs of the brown-toad resemble, in most 
respects, those of the green-frog. In two specimens, out 
of many that I have dissected, I have found the kidneys in- 
corporated at their upper ends. The ureters have the same 
termination nearly. The bladder of urine appears to be 
double ; when distended fully with air, it resembles two oval 
bags; the compartments communicate freely just above the 
symphysis pubis, to which they are firmly attached ; and 
they have but one orifice into the rectum, which is as well 
suited as in the former instance, for the reception of the urine 
as it flows into the rectum. 
The urine of the bull-frog, taken from the bladder imme- 
diately after the death of the animal, varies a little in its ap- 
pearance in different instances ; and, of course varies consi- 
derably in quantity, the bladder being sometimes full almost 
to distension, and at other times quite empty. The following 
js a description of a quantity of urine amounting to 300 grains 
which was collected from thirty-six frogs of different sizes : 
