420 CLASS MAMMALIA. 



and compressed laterally toward the extremity; two ingui- 

 nal mammae. 



The horns of this genus present a singular character : 

 they do not envelop a bony axis, like the horns of 

 the ruminating animals, nor do they partake of the osse- 

 ous nature of the horns of stags, but they appear to be 

 formed of horny fibres, like thick hairs closely agglutinated 

 together. There is much room for observation on the 

 structure of these horns, but instead of attempting any 

 remarks of our own upon the subject, we shall illustrate it 

 much better by transcribing what has been already so ably 

 observed by Mr. Burchell. 



" The horn of the Rhinoceros (says he) differing in struc- 

 ture from that of every other animal, and placed in a situ- 

 ation, of which it is the only example, had long appeared 

 to me to be an anomaly very deserving of examination; 

 and therefore on the present occasion (the first in which 

 he had inspected one recently killed) it was the first object 

 of my curiosity and attention. The view which I now be- 

 gan to take of its structure and nature, was afterwards, 

 in the course of my journey, further confirmed by the fol- 

 lowing mode of reasoning, which, to render it less com- 

 plicated, I shall confine to the class of Mammalia, or, as it 

 is more commonly called quadrupeds. Dispersed over the 

 skin of all animals are pores, which I have supposed to 

 secrete a peculiar fluid, which may be designated by the 

 name of corneous matter. This secretion, or fluid, is de- 

 signed by nature for the forming of various most useful 

 and important additamenta, all of which continue growing 

 during the whole life ; have an insertion not deeper than 

 the thickness of the skin, and are further distinguished by 

 the absence of all sensibility and vascular organization, 

 being purely exuvial parts, like the perfected feathers of 

 birds. In all these parts, the growth takes place by the 

 addition of new matter at their base. When these pores 



