SPIDERS AND OTHER ARACHNIDS 



119 



Mites and Ticks. — The mites and ticks are small arachnids 

 living on vegetation, in the water, or as parasites on men and 

 other animals. They will be more fully discussed in the next 

 chapter. 



King Crab. — The king or horseshoe crab (Fig. 66) is a pecul- 

 iar arachnid that lives in the sea and was for a long time con- 



acu/eus. )/ "vesicle 



Fig. 65. — Scorpion: A, dorsal view; B, ventral view. (After Kraepelin.) 



sidered a crustacean. The head and thorax form a large horse- 

 shoe-shaped piece and the tail is a single long spine. The king 

 crab lives in burrows in the sand and feeds on worms, snails, and 

 other small marine animals. 



Characteristics and Classification of Arachnida. — The mem- 

 bers of the class Arachnida differ markedly from one another, 



