190 Macteay Memortat Vo.ume. 
ON THE PECULIAR ROD-LIKE TACTILE ORGANS IN THE 
INTEGUMENT AND MUCOUS MEMBRANE OF THE 
MUZZLE OF ORNITHORHYNCAUS. 
By J. T. Witsoy, M.B., Proressor or Anatomy, Universiry or Sypney, anp C. J. 
Martin, M.B., B.Sc., Demonstrator or Puystotocy, University or SypNey. 
(Plates xx1v.-xxvi.) 
Some six months since, we were fortunate enough to have in our possession a live 
specimen of an adult Orvnzthorhynchus. We kept the creature in a cage containing 
a tank for three weeks. 
The animal usually procures its food by raking away in the mud at the bottom 
of rivers for small larvee, shellfish, insects, &e.* We fed ours on small snails and 
worms, which, together with water-weeds, were placed in its tank. At the end of 
three weeks we killed it in order to secure the tissues in a perfectly fresh condition 
for histological purposes. 
During the time it had been under observation, while it was alive, we noticed 
among other things the markedly sensitive nature of its so-called beak. This 
observation, together with the fact noticed by Meckel,t of the enormous development 
of the fifth pair of nerves (which are absolutely very much larger than the same 
nerves in man, notwithstanding the fact that the animal is only about a foot and a 
half in length) decided us to investigate the destination of these nerves. 
On removing the skin from the upper surface of the snout, the infra-orbital and 
nasal branches of the fifth nerves are seen emerging from their foramina and 
branching out in a brushlike manner towards the free margin of the snout. The 
infra-orbital foramina are placed in the Platypus at the lateral margins of the 
skeleton of the upper jaw, and their position is indicated by prominences of the 
bony contour of the jaw, to which the extreme hinder ends of the upper marginal 
cartilage are attached. (See our paper “On the Anatomy of the Muzzle of 
Ornithorhynchus” in this volume.) 
* Dr. George Bennett. Trans. Zool. Soc. Vol. I. p. 229. 
+ Ornithorbynchi paradoxi descriptio anatomica, 
