280 



REPTILES. 



[Chap. IX. 



curious horn-like process on the extremity of the nose. 

 This horn j as it is found in mature males of ten inches 

 in length, is five lines long, conical, pointed, and slightly 

 curved; a miniature form of the formidable weapon, 

 from which the Rhinoceros takes its name. But the 

 comparison does not hold good either from an anato- 

 mical or a physiological point of view. For, whilst 

 the horn of the rhinoceros is merely a dermal produc- 

 tion, a conglomeration of hairs cemented into one dense 

 mass as hard as bone, and answering the purpose of a 

 defensive weapon, besides being used for digging up the 

 roots on which the animal lives ; the horn of the cerato- 

 phora is formed of a soft, spongy substance, coated by 

 the rostral shield, which is produced into a kind of sheath. 

 Although flexible, it always remains erect, owing to the 

 elasticity of its substance. Not having access to a living 

 specimen, which would afford the opportunity of testing 

 conjecture, we are left to infer from the internal structure 

 of this horn, that it is an erectile organ which, in mo- 

 ments of irritation, will swell like the comb of a cock. 

 This opinion as to its physiological nature is confirmed 

 by the remarkable circumstance that, like the rudiment- 

 ary comb of the hen and young cocks, the female and 

 the immature males of the ceratophora have the horn 

 exceedingly small. In mature females of eight inches in 

 length (and the females appear always to be smaller 

 than the males), the horn is only one half or one line 

 long ; while in immature males five inches in length, it 

 is one line and a half. 



Among the specimens sent from Ceylon by Dr. Kelaart, 

 and now in the British Museum, there is one which so 

 remarkably differs from C. Stoddartii, that it attracted 

 my attention, by the peculiar form of this rostral ap- 

 pendage. Dr. G U-NTHER pronounced it to be a new 



