160 W. A. KIDD, ESQs, MsD., B.S: MiB.CS., -F-Z.83, ON 
as to cause him to say, “Thus the wonderfully diversified 
instincts, mental powers, and affections of ants are notorious, 
yet their cerebral ganglia are not so large as the quarter 
of a pin’s head. Under this point of view, the brain of 
an ant is one of the most marvellous atoms in the world, 
perhaps more so than the brain of a man.’* But, broadly 
speaking, ascending brain-power, shown not only by pro- 
portional weight and size of brain, but by complexity 
as well, marks all the vertebrate or chordate classes, 
especially mammalia. 
The striking fact in regard to characters for protection 
29 
is the diminishing power and complexity of “ passive 
structures, correlated with the increasing power, through 
higher intelligences, of employing the “active” characters 
subserving protection. 
The means subservient to the active protection of the 
body are such as the organs of movement, of sight, hearing, 
smell, taste and touch—claws, teeth, and horns. The 
various powers of burrowing, climbing, swimming, diving, 
walking, running, hibernating, exhibit some of the different 
methods adapted to the differing organizations of mammaha, 
and serving to protect them against a thousand and one 
dan gers. 
In regard to passive structures concerned in protection 
we find many still among mammalia, but in a markedly 
lower proportion to their multiplying needs than all that 
have gone before. The enumeration of the most common 
passive structures among mammalia, viz, hairy coverings 
of all degrees of thickness, spines, coloration, and markings 
for protection, and a few specialized forms, will show their 
comparative insignificance in this the highest class of 
animals. In truth a survey of this subject forces one to the 
conclusion that as animals ascend the zoological ladder they 
have increasingly to learn the art of living by their wits ; 
an art which naked-skinned, unprotected man has been 
compelled to study to perfection, in the course of many 
bitter lessons. 
We will here only mention the successive orders of 
mamialia, as given by Lyddeker, alluding briefly to the 
protective character of each. 
1. Monotremata possess fur, strong claws, and certain of 
them prickly spines. Marsupialia, or pouched animals 
* Descent of Man, i, p. 54. 
