APPENDAGES TO THE HEAD. 253 
head. The most striking instance of this is seen in 
the elephant; but it is no less remarkable in the ant- 
eaters, the shrews, and the mice; while the common 
term of “ pig-eyed,” proverbially applied to small- 
eyed people *, expresses the singular fact we are now 
illustrating. The whole family of humming birds 
have the longest bills, and the smallest eyes, in pro- 
portion to their size, of any birds yet discovered ; 
and these latter organs are placed so far from the 
naked part of the bill, that they seem central be- 
tween the nostrils and the nape. When, therefore, 
any such particular structure can be traced through 
animals of different genera, and even in totally dif- 
ferent classes, we feel assured that it must exercise 
an important influence in the system of nature, and 
that especial regard must be paid to such circum- 
stances, in characterising natural groups. Similar 
results would attend an investigation of all such 
animals as have, in opposition to the last, very short 
and thick muzzles. Appendages to the head, 
whether in the shape of horns, crests, protuberances, — 
or wattles, may be considered as furnishing strong 
and highly valuable characters of primary import. 
Horns are one of the chief characteristics of the 
ruminating order of quadrupeds— Ruminantia —in 
which is comprised not only the family of oxen, but 
the deer and antelope races. In these, the horned 
structure is at its maximum of developement, and 
consequently assumes the rank of an essential 
character. In the Pachydermate, or thick- skinned 
quadrupeds, belonging to the same order, we have a 

* It is very singular that “pig-eyed” people have very 
generally a long, but never an aquiline nose. 
