THE ORNITHORYNCHUS PARADOXUS. 41 
the small perforation existing, as well in the termination of 
the membranous canal, as in the spur itself, I am not pre- 
pared to say what may be the precise use of the small dark 
bristle-like body filling up, as it were, the extremity of the 
canal in the spur. It is not connected particularly with the 
membranous canal, but it must be evident that the poison- 
ous fluid may find its way to the point of the spur by the 
sides of the horny substance alluded to. Fluids injected 
into the duct, near its commencement in the gland^ pass , 
into that contained within the spur, and even out of the 
extremity of the latter ; and the pressure of a moderate co- 
lumn of quicksilver forced the metal to distil in excessively 
minute globules from the point of the spur. 
The accompanying engraving (Plate I.) scarcely requires 
any explanation. On the upper and back part of the thigh 
and loins may be seen the large poison-gland and duct leading 
from it towards the bottom of the foot; a small steel-probe 
has been passed along the duct into the sac, in order to 
show the mode of its entrance into the latter ; the bulb at 
the base of the spur, the membranous canal, and the spur 
itself, are all sufficiently distinct. 
