330 STALK-EYED CRUSTACEA 



(frequently the fourth pair) slender and small, prehensile, 

 or folded in the branchial chamber. 



The abdomen bent under the body or extended, with 

 appendages. Genital openings of the females on the 

 basal joint of the third pair of legs. 



Gills nine or more in number on each side. 



Range. — In all seas, more abundantly in hot or warm 

 climates ; they may be found on dry land or they may be 

 fluviatile, or range from the shore to extreme depths of 

 the sea. 



Group I. Dromidea. 

 Group II. Raninidea 

 Group III. Hippidea. 

 Group IV. Paguridea. 

 Group V. Galatheidea. 



Synopsis of the Groups. 



A. Last pair of legs small and subdorsal in position. 



a. Abdomen folded under the thorax, with, in the 

 female, five appendages, the first pair rudimentary. 



a^. Carapace subglobose or subquadrate. — {Droviiden?) 



b. Abdomen not folded under the thorax, with, in the 

 female, four pairs of appendages. 



b^. Carapace ovato-oblong. — {Raninidea^ 



B. The last pair of legs slender and filiform, folded 

 under the penultimate pair. 



c. Abdomen semi-extended, composed of six segments ; 

 the two terminal segments fused, the penultimate with 

 prominent pair of biramous lamellar appendages. 



c^. Carapace ovate or subquadrate. — {^Hippidea?) 



C. The last pair of legs small and frequently chelate. 



d. Abdomen usually asymmetrical. 



