I 
INTRODUCTION. 9 
round to revenge the indignity, and, like Russian gens- 
d’armes, seized upon the unsuspecting poles. These latter 
were slightly shaken by the fishermen, as if in pain or ter- 
ror ; the angry creatures clung all the closer, and were then 
rapidly hoisted into the boat. The moral we drew at the 
time, and have since maintained, was, that neither Crab nor 
Christian should ever lose his temper.” 
The following definition of Crustacea is that given by 
Professor Milne-Ed wards, in his classical work. - * Animals 
with the body divided into rings which are generally very 
distinct, moveable, and horny or calcareous, without an 
inner skeleton properly so called, and bearing a double 
series of members, almost always very distinctly articulated, 
and forming the antennae, jaws, etc., and legs, of which 
there are usually five or seven pairs. The nervous system 
is generally very distinct, ganglionic and longitudinal. The 
respiration is in general aquatic, and is always by the 
branchiae or the skin ; the circulation is in general very 
distinct ; there is almost always an aortic heart, and proper 
blood vessels. The sexes are separate. 
Many if not most of the Crustacea undergo, like Insects, 
* 4 Histoire Naturelle des Crustacea/ vol. i. p. 231. Many of the cha- 
racters in the following work are compiled from the Professor’s three vols. 
