The following are the sub-tribes of the Brachyura : 

 Ox vstom ata.— Mouth-Held prolonged forward as a 



gutter. No female first abdominal limbs. Gills 



few. Female openings sternal. 

 Dromiacea.— Mouth-field square. First abdominal 



limbs present in female. Gills many. Female 



openings coxal. 

 Brachygnatiia. — Mouth-field square. Female openings 



sternal. No first abdominal limbs in female. 



Gills few. 



The Brachygnatha are divided into two super- 

 families. 



Oxyrhyncha. — Front part of body narrow. Distinct 

 rostrum. Body more or less triangular. Orbits 

 incomplete. 

 Brachyrhyncha.— 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 nut 

 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. 



