78 INVEETEBRATE ANIMALS. 



Group 187.— Genus XANTHO (Leach) and allies. 



5[ Menippe gigas (M. Edwards) is probably the 

 most powerful Crustacean : the pincers are worked by a 

 muscular apparatus enormously developed, and must be 

 capable of crushing with ease the shells of many bivalve 

 Mollusca. Much variety in colour and sculpture is met 

 with amongst the smaller generic forms. 

 Estimated number of species : recent, 50 ; British, 2. 



^ Examples of ChlorocUus, Etisus, Daira, Actce- 

 odes, &c. 



Group 188.— Genus CARPILIUS (Leach) and alhes. 

 Estimated number of species, 24 ; British, 0. 



IT C. coralinus, C. maeulatus, and the rare C. sig- 

 natus afford good examples of the smooth, 

 convex, and highly-coloured shields which pre- 

 vail in this group ; Atergatis, Zozymus, &c. 



Section D. — Crahs ivith shields more or less triangular, much 

 narroived in front = Famille des Oxyrhinquees (Milne 

 Edwards). 



Group 189.— Family PARTHENOPID^. The species all 

 live amongst rocks in moderately deep water ; they move 

 slowly and notwithstanding their grotesquely rugged 

 aspect cannot be formidable except to animals much 

 inferior in size to themselves. The single British spe- 

 cies, the Strawberry-crab, is said to use its long arms in 

 climbing. 

 Estimated number of species, 20 ; British, 1. 



