280 
REPTILES. 
[Chap. IX. 
curious horn-like process on the extremity of the nose. 
This horn, 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 0De 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 G. titoddartii, that it attracted 
my attention, by the peculiar form of this rostral ap- 
pendage. Dr. Gun thee pronounced it to be a new 
