DECAPODA. BBACHYURA. 543 



the broad thoracic sterna. Pterygostomial region fused in front 

 with the epistome, and not separated by a movable suture from 

 the rest of the carapace. A median ridge unites the epistome 

 with the rostral region of the carapace. The eyes and first 

 antennae are received in pits of the cephalo-thorax. The second 

 antennae project on the inner side of the eye stalks. Both 

 pairs bear short flagella. The endopodite of the first maxilliped 

 is broad, un jointed and terminates in a well marked outer angle. 

 The third maxillipeds are broad and opercular. The first trunk- 

 legs alone are chelate. The abdomen is narrow in the male and 

 bears only the one or two anterior appendages (copulatory) ; 

 wide in the female, with 4 ovigerous fan-like appendages ; 

 but the sixth pair (uropods) is never present. The gills are 

 phyllobranchiate. In nearly all cases the eggs hatch as zoaea 

 larvae, with the two pairs of biramous swimming maxillipeds, 

 and long spines (dorsal, frontal and paired lateral). A metazoaea 

 and megalopa stage are passed through, but a mysis stage is 

 absent from the life-history. 



Tribe 1. BRACHYURA ANOMALA. 



Fourth and fifth trunk-legs articulated higher than their predecessors ; 

 epistome * broad ; as many as 14 pairs of gills may be present and the 

 openings of the oviducts are on the bases of the third trunk legs, not on 

 the adjacent sterna. In these two features the members of this family 

 differ from the other Brachyura and resemble the Macrura, with which 

 group they are often classified. 



Fam. 1. Homolidae. Eye-stalks long and usually slender ; orbits 

 and fossae for first antennae incomplete or absent ; last pair of legs 

 small, and prehensile. Tropical and subtropical, down to 825 faths. 

 Dicranodrornia A. M. Edw., intermediate between this and the next sub- 

 family, but with incomplete orbits and no fossae for 1st antennae. 

 Homola Leach, carapace quadrilateral ; 14 pairs of gills. 3rd maxilliped 

 leg-like. Latreillia Roux, carapace triangular, legs slender and cylindri- 

 cal with a superficial resemblance to spider-crabs. 



Fam. 2. Dromidae. Carapace usually sub-globular ; orbits well 

 defined ; 5th and usually 4th trunk-legs short, prehensile and used for 

 carrying a shell, sponge, ascidian colony or other sheltering object over 

 the back ; 14 pairs of gills. Dromia Fabr. carapace pilose. D. vulgaris 

 M. Edw. Mediterranean, sometimes British, with a strange shaggy 

 aspect ; regarded as " poisonous and narcotic," by the ancients ; male 

 copulatory organs large. Petalomera Miers ; Dynomene Latr. only the 

 5th legs sub-dorsal. 



* The epistome is, as stated above, the region between the front of the 

 carapace and the anterior border of the mouth ; the latter being well 

 marked in the Brachyura. The terms broad and narrow in the following 

 descriptions apply to the antero-posterior dimensions of the epistome. 



