I2O 



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. 



