ORNITHORYNCHUS PARADOXUS. 29 



" We may now trace this duct either from the sac towards the 

 gland, or vice versa. If the first plan be adopted, we perceive 

 that the duct enters the central sac by a small round orifice, and 

 next makes a very sudden turn to reach the superficial part of the 

 foot, and is soon found almost immediately under the integuments. 

 From this point it proceeds towards the gland, gradually decreas- 

 ing in strength of parieties, but increasing in diameter until it 

 terminates, or rather commences, in the poison-gland itself, situated 

 over and somewhat above the hip joints and loins. Throughout 

 its course the duct lies imbeded in loose cellular membranes, and 

 beneath the caudo-tibial muscle, which must be removed, in order 

 to have a perfect view of the duct. Is is rather difficult to state 

 the precise length of the duct from its origin in the poison -gland 

 to its passage into the small sac, situated in the hollow of the foot ; 

 for about eight-tenths of an inch its parieties are comparatively 

 thin, and its diameter sufficient to admit a common blow pipe. 

 The remainder of the duct, and the sudden turn it makes to pass 

 down into the centre of the foot and to reach the sac, have been 

 already described. 



" The poison -gland itself is about an inch in length, and six- 

 tenths of an inch in breadth. It is a conglomerate gland, that is, 

 made up of small ones, imbeded in a tissue of different appear- 

 ance, and which is probably cellular. It lies longitudinally with 

 respect to the spine, immediately above the hip-joint, and close to 

 the os innominatum of the corresponding side. It advances but 

 little towards the loins; it covers many of the muscles which 

 rotate the thigh, and may readily be found by merely removing the 

 integuments, panniculus carnosus, and a small quantity of loose 

 cellular membrane lying over the os innominatum and hip-joint. 



" The functions of these parts may now be very readily under- 

 stood. The poisonous fluid secreted by the gland, is conveyed by 

 the long duct into the sac, situated deep in the hollow of the foot, 

 close to the heel. From this it is projected into the membranous 

 canal contained in the centre of the spur, and which, by an almost 

 inexpressible error, has hitherto been mistaken for a bone. Along 

 this it will easily flow into the wound inflicted by the spur, passing 



