232 



SUBKIHGDOM ABTICULATA. 



a. T^rilrux locusta ; 

 b. Orchestra longicornis, Sand-fleas. 



ORDER TETRADECAPODA. 



General Characteristics. The Tetradecapods (four- 

 teen-footed) have sessile 

 (low-sitting) eyes and 

 all the segments of the 

 thorax free. 



The Amp bipods 

 Lave the four anterior 

 pairs of feet directed 

 forward and the three 

 posterior backward. 

 They live in both salt 

 and fresh water, and 

 are abundant on the 

 sea-shore between tide- 

 marks. (Fig. 395.) 



The Isopods have a flattened body, Fig. 395. 



the three anterior pairs of feet directed 

 forward and the four posterior pairs A 

 backward. The gills are borne under 

 the abdomen. Soiv-bugs are familial- 

 examples. 



ORDER PHYLLOPODA. 



General Characteristics. The 

 Phyllopods have from 10 to 60 pairs 

 of leaf-like feet, answering the purpose 

 of gills. They are found in both salt 

 and fresh water. Fig. 396 represents 

 a species discovered by Dr. E. Coues, 

 in small prairie pools in Montana. 



LepidUms couesii. 



Hermit Crab Is protected only in front, and eo "backs'" into the spiral shells oi 

 other Mollusks, leaving its temporary home only when outgrown. The Marine 

 Lobster has a broad fin at the base of its tail, by one stroke of which it can spring 

 backward twenty feet. 



