322 



THE ANATOMY OF IXVERTEBRATED AXIMALS. 



shield, is formed by a very large setose labrum, behind and 

 below which, in the middle line, is the extraordinarily minute 



Fig. 85.— a diagram of the body of a Scorpion, the majority of the appendages be- 

 ' ing removed : a, the mouth ; f), the alimentary canal ; c, the anus ; d, the heart ; 

 «, a pulmonary sac ; /. the positi m of the ventral ean>j:lionated cord ; g, the cere- 

 bral sang\i{i;'T. the telson. VIl-XX, the seventh to the twentieth somite. IV, 

 V, VI, the basal joints of the pedipalpi, and two following pairs of limbs. 



aperture of the mouth (Fior. 86, 31). On each side of it is 

 attached a three-jointed, pincer-ended, appendage, the che- 

 licera. Behind these follow the pedipalpi, large chelate limbs, 

 the stout basal joints (iv') of which lie on each side of the 

 mouth. 



The following four pairs of appendages are seven-jointed 

 ambulatory limbs, each terminated by three claws. The ba- 



