456 STALK-EYED CRUSTACEA 



B. The second pair of legs 

 has usually a large hand ; fifth 

 joint is composed of one piece. 

 — ( Monocarpidea?) 



Monocarpidea. 



Tribe I. Polycarpidea. 



Polycarpidea .... Spence Bate. 



The second pair of legs is slender ; their fifth joint, 

 carpus, is divided into many joints. 



Family I. Nikidae. 



Family II. Alpheidae. 



Family III. Hippolytidae. 



Family IV. Pandalidae. 



Synopsis of the Families. 



A. The first pair of legs simple or armed with pincers, 

 the second pair minutely so. 



a. Rostrum horizontal with dorsal surface. — {Nikidcu^ 



^^s:^ 



Nikida. 



B. Of the first pair of legs, the pincers on one side are 

 of normal form ; on the other side, of irregular form. The 

 second pair of legs has pincers. 



b. Rostrum short or wanting. Eyes covered by the 

 carapace. — {Alphcidce.) 



