Legs of 1st 

 pair 



cheliform. 

 distinctly 



Uropoda 

 developed, 



terminal. Pleopoda, when! . 



J 1. Chelifera. 



exclusively natatory. 



not cheli- 

 form. 



Uropoda 

 lateral, 



Uropoda 

 terminal. 



forming together with the 

 terminal segment of the 

 metasome a caudal fan. 

 Pleopoda for the most part 

 natatory. 



valve-like, inflexed, arching 

 over the pleopoda, which 

 to a great extent are bran- 

 chial. 



Pleopoda exclusively bran- 

 chial, generally covered by 

 a thin opercular plate (the 

 modified 1st pair.) 



2. Flabellifera. 



Valvifera. 



4. Asellota. 



Pleopoda fitted for air-) . 



| o. Omscoidea,, 



breathing. 



Pleopoda, when present, ex- 

 clusively branchial in the 

 adult animal, and not cov- 

 ered by any operculum. 



6. Epicarida. 



