24 A HISTORY OF RECENT CRUSTACEA 
CHAPTER IIl 
MAGNITUDE 
In zoology, size attracts attention in comparison with 
two standards. Man contrasts the bulk of an animal 
either with the average in his own order or with that of 
the group to which the particular animal belongs. An 
elephant is a huge beast, not in competition with a whale, 
but with a human being. A hornet less than a man’s 
little finger is a monster beside a house-fly or a gnat. As 
in all classes the majority of individuals conform pretty 
closely to the average magnitude, the mind becomes 
trained to regard the exceptional extremes with wonder, 
often not unmingled with admiration when the mass is 
not smaller but greater than common. Among the Crustacea 
there are forms, not indeed surpassing all others in 
diminutiveness, but at any rate so exceedingly small that 
the sharpest eyes could perhaps never have found out that 
they were crustaceans without the aid of the microscope. 
Here it is that the philosophical naturalist sometimes finds 
chief reason to marvel, in perceiving the whole machinery 
of life, enabling active locomotion, nutrition, and repro- 
duction, with senses, a power of choice, and the capacity 
for feeling pleasure and pain, all packed away as neatly 
and conveniently as possible in so extraordinarily small a 
casket. For preliminary studies creatures of more con- 
siderable compass hold an obvious advantage, and with 
most observers it is rather the giants of an order than 
the dwarfs that are deemed especially remarkable and 
worthy of the notice which they are fitted readily to 
engage. Some of the old writers probably understood 
