28 OUNITHORYNCHUS PARADOXUS. 



black body, like a bristle projects ; it seems of a horny consistence ; 

 though a strong magnifying glass was used, it did not appear to be 

 hollow. On removing the integuments carefully, the spur is found 

 to rest by its base on a flat bone, placed longitudinally over the 

 tarsal bones, and situated between the lower extremity of the tibia 

 (to which it is attached) and the tarsal bone corresponding to the 

 inner toe. Its principal connection, however, is at the astragalus. 

 In this way two joints are formed ; viz. one between the bone on 

 which the spur rests and the other bones of the tarsus, and the 

 other between the spur itself and the bone. The motion in both 

 these joints is inwards towards the tail, and this is the direction 

 which the spur assumes, and the only one in which it can possibly 

 wound. If a longitudinal section be made of the spur, it will be 

 found to contain a comparatively large membranous canal, gradually 

 increasing as we proceed towards the base ; this membranous canal 

 is contained in the centre of the spur, which, immediately around it, 

 has a whiter appearance than the more external portions, but has 

 no resemblance to bone, as some estimable authors have stated. 



" As the membranous duct approaches the base of the spur, it 

 becomes very strong, as if semi-cartalaginous tunics were super- 

 added to it ; just as it quits the spur to enter the sole of the foot, 

 the duct makes a sudden turn, and is much contracted ; it next 

 expands a little, and at this point its parietics show so as to give it 

 the appearance of a bulb or gland, an appearance which together 

 with the deep situation of the sac in the hollow of the foot, led 

 M. de. Blainville to consider it as the poison -gland itself, and which 

 evidently has been the cause of the singular errors relative to 

 the anatomy of the spur. When this bulb is laid open, it is found 

 to be merely a continuation of the mucous canal, which has at 

 this point become greatly strengthened in its parieties, and as- 

 sumed an almost muscular appearance. Tn the hollow of the foot 

 the duct opens by a sudden turn into a comparatively large sac, 

 sup-ounded and inclosed by strong ligaments, and tendinous parts, 

 connected with the small bones of the foot. From this sac or bag, 

 which in either foot contained a good deal of a brownish mucous 

 matter, arises the great duct leading to the poison-gland. 



