120 



PRACTICAL ZOOLOGY 



but agree in several important respects: (i) they have no an- 

 tennae; (2) there are no true jaws; (3) the first pair of append- 

 ages are nippers, termed chelicerae; and (4) the body can usu- 



FiG. 66. The king or horseshoe crab : A, dorsal view ; B, ventral view. (From 



Shipley and MacBride.) 



ally be divided into an anterior part, the cephalothorax, and a 

 posterior part, the abdomen. 



Of the twelve orders of Arachnida only four need be mentioned, 

 since they contain most of the living species. 



Order i. ARANEIDA. -- Spiders. 



Order 2. SCORPIONIDEA. -- Scorpions. 



Order 3. PHALANGIDEA. - - Harvestmen, or Daddy Long- 

 legs. 



Order 4. ACARINA. -- Mites and Ticks. 



REFERENCES 



The Spider Book, by J. H. Comstock. Doubleday Page and Co., N. Y. 



City. 

 Common Spiders, by J. H. Emerton. Ginn and Co., Boston. 



