The following are the sub-tribes of the Brachyura : 

 OXYSTOMATA. Mouth-field prolonged forward as a 

 glitter. No female first abdominal limbs. Gills 

 few. Female openings sternal. 



DKOHIACEA. Mouth-field square. First abdominal 

 limbs present in female. Gills many. Female 

 openings coxal. 



BBACHYGNATHA. Mouth-field square. Female openings 

 sternal. No first abdominal limbs in female. 

 Gills few. 



The Brachygnatha are divided into two super- 

 fa,milies. 



OXYIIHYNCHA. Front part of body narrow. Distinct 

 rostrum. Body more or less triangular. Orbits 

 incomplete. 



BKACHYRHYNCHA. Front part of body broad. Rostrum 

 reduced or wanting. Body oval. Orbits com- 

 plete. 



The Brachyrhyncha are sub-divided into fourteen 

 families. I give here the chief characters of the one 

 family the Cancridae. 



CANCRIDAE. Marine crabs with the branchial region 

 not greatly swollen. Carapace broadly oval or 

 hexagonal. Rostrum often wanting. Orbits com- 

 plete. Male openings coxal. Second antennal 

 flagella short. First antennae folded length- 

 wise. Inner lobe on the endopodite in the first 

 maxillipedes wanting. Legs generally not 

 adapted for swimming. 



The two sub-families of the Cancridae are as 

 follows : 



PIRIMELINAE. Carapace hexagonal. Epistoma sunken. 

 CANCRINAE. Carapace broadly oval. Epistoma not 

 sunken. 



