792 ARACHNIDES—SCORPION. 
on different animals. In general, they are carnivorous, and suck the >lood 
of their prey or animals. A small number only feed on vegetable m \tters 
Many have mandibles which exercise the office of a sucker; and others have 
an isolated sucker, often, however, joined with mandibles and palpi. The 
terrestrial species are in general solitary animals, and of a forbidding aspect, 
and many of them shun the light, and live in concealment. Several of these 
are poisonous, and their bite dangerous. Lamarck divides the class of Arch- 
nides into three orders, viz: First, Those destitute of antenne, furnished 
with branchial sacs for respiration, and with six to eight eyes. Second, 
Those destitute of antenne, with branched trachea for respiration, and with 
two or four smooth eyes. Third, Those with antenne and gangliated tra- 
chia for respiration; while Latreille arranges the class into two orders, ac- 
cording to the characters of their branchial apparatus. 
Order I. PutmMonarrz.—With pulmonary sacs for respiration; a heart 
and distinct vessels. 
Order Il. TracnEartr®.—Respiring by trachez, and the organs of cir 
culation indistinct. 
THE SCORPION. 

There are four principal parts distinguishable in this animal; the head, 
the breast, the belly, and the tail. The scorpion’s head seems, as it were, 
joined to the breast; in the middle of which are seen two eyes; and a little 
more forward, two eyes more, placed in the fore part of the head; these 
eyes are so small, that they are scarcely perceivable; and it is probable the 
animal has but little occasion for seeing. The mouth is furnished with two 
jaws; the undermost is divided into two, and the parts notched ‘nto each 

1 The genus Scorpio has two large palpi in the form of arms, the *ast joint thickest, 
and in the form of forceps ; mandibles short, narrow, and didactyle ; ore short, rounded ; 
eyes six or eight; body oblong, divided into many segments, with a long, knotty, tail ter- 
minated in an arched sting; two pectinated and moveable plates under the belly at the 
base of the abdomen; four spiracles on each side; eight feet. 
