Decapod Crustacea of Bermuda, Part II. 35 



d. Cephalon and pleon not abnormally elongated ; podobranchiae lacking 

 or present only on second maxillipeds ; arthrobranchiae few., sometimes 

 present on the second and third maxillipeds and first to third legs ; 

 branchial filaments are flat. Last two pairs of legs small and feeble, 

 the fifth sometimes absent. 



Family Sergcstida. 



dd. Cephalon and pleon generally much elongated ; branchiae lacking ; 

 fourth and fifth pairs of legs absent ; no exopodites nor epipodites on 

 the legs. 



Family Lcucifendtr. 



AA. The epimera of first abdominal segment are covered by those of 

 the strongly developed second segment. Third pair of legs not chelate. 

 Branchiae are phyllobranchiate, composed of thin, flat lamellae and not 

 branched. Antennules usually have two flagella, the outer one 

 thickened and distally branched. 



Tribe Caridea or Phyllobranchiata. 



C. Second pair of legs long and slender, with the carpus subdivided into 

 few or many articles or annuli, and with very small chelae. First 

 pair larger, with stronger chelae and undivided carpus. 



Group Poly car pidca. 



D. Eye-stalks very short ; eyes usually nearly or entirely covered by lobes 

 of the carapace ; rarely exposed. First pair of legs large, with large 

 unequal chelae, one usually very large, rarely equal. Rostrum usually 

 small and simple, acute, -sometimes obsolete. Carpus of second pair 

 of legs with five articles. A cardiac pit in carapace. 



Family Synalpheldce (formerly Alpheida). 



DD. Eye-stalks and eyes not covered by the carapace ; carpal segments 

 various ; no cardiac pit. 



E. First pair of legs chelate, or at least one is chelate. 



F. Eyes very small on long slender stalks. Female has a thelecum ; 

 uropods are excurved. Legs of second pair have the carpus divided 

 into three or four articles ; both of first pair chelate ; third maxil- 

 lipeds slender, last article shorter than preceding one ; rostrum small 

 and short. 



Family Ogyridce. 



FF. Eyes large, on short stalks ; no thelecum ; uropods not excurved ; 

 carpus of second pair of legs has few or many articles ; third maxil- 

 liped usually has the last article longer than the preceding. 



G. Rostrum usually of notable size and serrate. First pair of legs with 

 rather small equal or subequal chelae, larger than those of second pair ; 

 second pair slender, with few or many carpal articles. 



Family Hippolyfidtr. 



GG. Rostrum small. First pair of legs commonly with only one leg 

 chelate ; those of second pair very slender, unequal in length ; carpal 

 articles numerous, more than five. Mandible has no palpus. 



Family Proccssida. 



