StruSlure of the Ornithorynchus Paradoxus. 367 



The conformation of the cranium, taken from the occi- 

 pital condyli {cd), and the intermaxillary bdnes {ef)y has, 

 on the firft view, a great refeniblance to tliat of the duck. 

 The bones of the fladl are divided by no futures ; but the in- 

 terior chamber of the brain is divided by an olTeoas hook [g) 

 running lengthwife, which is found in no other quadruped *, 

 and fimilar to that of the tctrao urogallus. 



What feems to be highly worthy of notice, however, is 

 the remarkable apparatus of the nerves of the fecond branch 

 of the fifth pair, and the ditlribution of it in three regions of 

 the coriaceous membrane which fiirrounds the beak. The 

 nerve {h) which proceeds from the lower orbital foramen 

 goes to the tranfvcrfe edge : the other (i), which ifTues be- 

 hind the intermaxillary bones, is diftributcd on the labial 

 edges : the third (/>), which iilues from the fynchondrofis, 

 that divides the anterior hooked legs of the intermaxillary- 

 bones, proceeds to the integument of the beak. 



Comparing this large apparatus of maxillary nerves, with 

 •which nature has provided this coriaceous integument, and 

 the like liructure of the duck's bill, there can fcarcely be a 

 doubt that this higlilv f^-nfible membrane, which furrounds 

 the beak, ferves, in a verv particular manner, in the ornitbo- 

 rj'iichus, as in aquatic birds, for the purpofes of feeling, by 

 means of which thefe animals can fearch for their food in 

 muddy places, where neither fight nor fmell can be of any 

 ufe to them in that rcfpeft. Hence the eyes of the ornitho- 

 rvTichus are very fmall, but the noftrils {Im) exceedingly 

 broaj. 



This wonderful animal, therefore, affords an exception to 

 the order of the internal ienfes affigned to quadrupeds by 

 Buffonf, who fays : " In quadrupeds, fmell is the firft of 

 ienfes ; tafie is the fecond ; or rather, thefe two form only 

 one: fiacht is the third; hearing the fourth; and feeling the 

 lad." '' 



In the annexed figure, one of the bones of the fkull is re- 

 prefented broken, that the interior of the chamber of the 

 brain may be feen. N, denotes the orbita; O, the zygoma; 

 I'Q, the prpccffus molares of each mandible. The other 

 parts will be undcrftood from the precedmg defcription. 



* I once fjf)und, but tlie iiiflancc is very rare, a fimilar offcous hook in the 

 a'jniiMii of H woman about tliiity years of age. 

 f Hiiloire des Oifcaux, toiii. 1. p. 48. 



LX. On 



