480 



STALK-EYED CRUSTACEA 



the second segment cover the first and third. Telson long, 

 and gradually narrowing to a truncated extremity. Eyes 

 well developed and pyriform. Antennae long and slender ; 

 internal pair having the first joint of the peduncle hollowed 

 on the upper surface, carrying a well-developed spine on 

 the outer side, and terminating in two flagella, of which 

 one is frequently branched ; external pair has a long, 

 narrow, foliaceous basal scale, the outer margin of which 

 is rigid and armed with a small tooth. Mandible has a 

 molar process, a cutting edge, and a palp. - The external 

 maxillipedes are pediform. First and second pair of legs 

 have pincers. Abdominal appendages two- branched. 

 Swimming organ well developed. 



rahvuiou. 



Synopsis of the Genera. 



I. Rostrum deep, serrate above and below. Three 

 flagella on internal antennae. The second segment of the 

 abdomen overlaps the firstand third 

 with its expanded lower margin. 



A. The fifth joint of the second 

 pair of legs is long. 



a. There are two spines on the 

 frontal margin of the carapace, one 

 above the other. — {Palcsnioii^ 



b. There is one spine on the frontal 

 margin of the carapace, and behind it, 

 but a little lower down, is a second 

 spine. — {Bithyiiis.) 



B. The fifth joint of the second 

 pair of legs is short. 



c. There is one spine on the frontal 

 margin of the carapace, and a second 

 spine behind it, but on a lower level. 

 — {Brachycarpus.) 



Bithyuis. 



Brachycarpus, 



