3182 



THE JOINTED ANIMALS 



including living and extinct species, has been divided into two sections, the Apoxy- 

 podes, or those with pointed feet, including the Silurian Palceophonus, and the 

 Dionychopodes, or those in which the feet are tipped with a pair of movable claws. 

 This last group is again divisible into the Anthracoscorpii, or scorpions of the Coal 

 period, in which the median eyes are in front of the lateral, and the Neoscorpii, or 

 recent forms, in which the median eyes are placed further back. 



In habits the different species seem to vary but little, most of them being 

 nocturnal and all of them exclusively carnivorous, feeding upon any living creature, 

 weak enough to be overpowered. They seem, however, to be largely dependent 



upon chance for the capture of prey; 

 for although provided with a large 

 number of eyes, vision is so defective 

 that they cannot see more than a few 

 inches, and there is no evidence of 

 the existence of any organs of hear- 

 ing. The sense x>f touch, however, 

 which resides in the hairs with which 

 the body and limbs are studded, is ex- 

 ceedingly keen. No sooner does an 

 unwary insect approach within reach 

 than it is seized in the vice-like grip of 

 the scorpion's pincers; then quick 

 as lightning the tail is brought into 

 use, and the sting plunged into the 

 struggling prey, which, as a rule, 

 quickly succumbs to the paralyzing 

 effect of the poison.' If, however, 

 the prey be of large size, and 

 muscular in proportion, the process 

 of stinging is repeated; but it has 

 been noticed that the scorpion in 

 most cases carefully selects a soft 

 spot into which to thrust its weapon, 

 and does not strike at random. The 

 object of this caution is evidently to 

 avoid all risk of breaking the point 

 of the sting against too hard a sub- 

 stance. The same care is shown in 

 the carriage of the tail, this organ 

 when not in use being almost always 

 kept curled up in such a manner 

 that the sting is securely protected. 

 Having imperfectly developed vision- 



AFRICAN ROCK SCORPION, Scorpio viatoris. ary powers, and no tactile antennae 

 (Natural size.) to supply this deficiency, scorpions 



