VOL. XC.] PHILOSOPHICAL TRANSACTIONS. 747 



exactly the same purposes ; it will however be found to differ materially from it, in 

 a variety of circumstances. The beak is found, on examination, not to be 

 the animal's mouth, but a part added to the mouth, and projecting beyond it. 

 The cavity of the mouth is situated as in other quadrupeds, and has 2 grinding 

 teeth on each side, both in the upper and lower jaw; but, instead of incisor teeth, 

 the nasal and palate bones are continued forwards, lengthening the anterior nostrils, 

 and forming the upper part of the beak ; and the 2 portions of the lower jaw, in- 

 stead of terminating at the symphysis, where they join, become 2 thin plates, and 

 are continued forwards, forming the under portion of the beak. This structure 

 differs materially from the bill of the duck, and indeed from the bills of all birds, 

 since in them, the cavities of the nostrils do not extend beyond the root of the bill; 

 and, in their lower portions, which correspond to the under jaw of quadrupeds, the 

 edges are hard, to answer the purpose of teeth, and the middle space is hollow, to 

 receive the tongue. But in this animal the 2 thin plates of bone are in the centre ; 

 and the parts which surround them are composed of skin and membrane, in 

 which a muscular structure probably is enclosed. 



The teeth have no fangs which sink into the jaw, as in most quadrupeds, but 

 are imbedded in the gum ; and have only lateral alveolar processes, from the outer 

 and inner edges of the jaw, to secure them in their places, but no transverse ones 

 between the 2 teeth. The tongue is extremely short, not half an inch long ; and 

 the moveable portion not more than a quarter of an inch ; the papillae on its sur- 

 face are long, and of a conical form. When the tongue is drawn in, it can be 

 brought entirely into the mouth ; and when extended can be projected about a 

 quarter of an inch into the beak. The organ of smell in this animal, differs in 

 some particulars from that of the quadrupeds in general, as well as of birds. The 

 external openings of this organ are placed nearly at the end of the beak, there 

 being only the lip beyond them , while the turbinated bones are in the same rela- 

 tive situation to the other parts of the skull as in quadrupeds ; by which means, 

 there are 2 cavities the whole length of the beak, superadded to the organ of smell. 

 The turbinated bones in each nostril are 2 in number, and are distinct from each 

 other. That next the beak is the longest, has a more variegated surface than in 

 the duck, and has the long axis in the direction of the nostril ; the posterior one 

 is short, projects farther into the nostril, and the ridges are in a transverse direc- 

 tion. The posterior nostrils do not open directly under the turbinated bones, as 

 in the duck, but about an inch farther back, and are extremely small ; the cavities 

 of the nose, in this animal, are therefore uncommonly extensive ; they reach from 

 the end of the beak nearly to the occiput. 



The beak itself is formed by the projecting bones already mentioned, covered 

 with a smooth black skin, which extends some way beyond the bones, both in 

 front and laterally, forming a moveable lip. This lip is so strong, that when dried 

 or hardened in spirit, it seems to be rigid ; but when moistened is very pliant, and 

 has probably a muscular structure. The under portion of the beak has a lip equally 



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