B THE HORNS. 29 
firmly attached to the horn, and many of them, towards the 
lower part, passing quite through it. We see the core of the 
horn is covered with a thick vascular skin, which is pretty well 
covered with the same kind of hairs as those seen in the cavity 
of the horn. We now appreciate that these hairs grew from the 
skin, and more or less penetrated the shell or horn, and when 
this was removed some were torn from the skin and others from 
the horn. 
We observe, further, that the new horn had commenced its 
growth a considerable time before the old one was cast, for the 
new horn was extended several inches above the top of the core, 
nearly in a vertical direction, though with a slightly posterior in- 
clination. The top of this, for nearly half an inch, is already 
hardened into perfect horn. Below this it is softer, and a little 
, way down it has lost the horny texture, but is a pretty firm and 
somewhat flexible mass down to the core and around it, at the 
upper part of which, however, it has rather the appearance of 
thick, massive skin, of a high temperature, showing great activity 
in the blood-vessels permeating it. As we pass lower down, the 
skin is thinner, and shows less excitement or activity. Upon 
this skin enveloping the core, we find the hairs already described. 
This was the condition of the new development when the old 
horn was cast off. It shows that the new horn had already made 
considerable upward growth from the top of the core, which only 
extended up into the old horn a little above the snag, or about 
half its length; all above this, of the old horn, was solid, and 
was not intersected by the hairs as it was below. 
Now it is perfectly manifest that as the new horn was extended 
in length above the core, it must have carried with it the old 
horn which it detached from the core, and tearing out the hairs, 
the roots of which were in the skin, and many of which extended 
into or through the old horn. Until these were mostly torn 
asunder, or were withdrawn from the canals by which they had 
penetrated the shell, they served to prevent it from being easily 
lost ; but finally, when these were all or nearly all severed, it fell 
off, as a favorable position occurred, or some slight violence as- 
sisted the removal. I have never observed the animal to assist 
this process by rubbing its horns against convenient objects, but 
my opportunities have not been such as to authorize the state- 
ment that they do not sometimes do so. 
When the old horn was cast off, the new one, as we have 
already seen, had made a considerable growth above the core, 
