OF THE STURGEON. 
357 
and is much firmer, and more consistent, than in the hu- 
man subject. 
The vessels of the ahmentary canal are found at the 
posterior surface of the different bowels covered by perito- 
neum. 
The urinary organs of the sturgeon consist of two long 
tubular canals, placed on each side of the intestine with 
the spiral valve, and resting on the spinal column and its 
muscles, to which they are attached by cellular membrane. 
To describe these organs is no easy matter ; they resemble 
neither the kidneys, nor the ureters, nor the bladder of the 
mammalia or birds, but combine the characters of all these. 
Their parietes are thin and membranous. Their inner 
surface, which is red, smooth and mucous, but not distinct- 
ly villous, presents a series of minute orifices not larger 
than pin-heads, which correspond to the infundibula of the 
kidneys of mammiferous animals. The lower extremities 
of these canals widen, and, suddenly contracting, terminate 
in a common outlet or vent, which opens behind that of the 
intestine on the surface at the anal fin. 
I may add also, that we saw the openings which main- 
tain the communication with the peritoneal cavity and 
the surface of the body, and which in these animals are re- 
quisite for the purposes of reproduction. I am aware that 
these singular outlets, by which a direct communication is 
established between the surface and cavity of the perito- 
neum and the surface of the body of the animal, have been 
the subject of some controversy ; and by some even their 
existence has been called in question. In this specimen, 
however, they were distinct ; and as their existence is not 
cpnfined to the sturgeon, they cannot be denied on the 
ground of anomaly, as I shall take occasion afterwards to 
show. 
