542 CRUSTACEA MALACOSTRACA. 



like. Scale of 2nd antenna rudimentary or 0. Abdomen ventrally flexed,. 

 but not folded against the sternum. Littoral and deep sea. 



Sub-fam. 1. Galatheinae. Eyes well developed. Exopodite of 1st 

 maxilliped ending in a flagellum. Galathea Fabr. Eye-stalk little 

 or not at all widened distally, rostrum triangular. Thirty littoral 

 spp., some British. Munida Leach. Eye-stalk widened distally, 

 rostrum spine-like. Thirty spp. littoral to deep sea. M. Rondeletii 

 (Fig. 315), British. 1st trunk-legs very long. Pleuroncodes Stps. 



Sub-fam. 2. Munidopsinae. Eyes reduced. Exopodite of 1st 



maxilliped without a flagellum. Deep sea. Galacantha A. M.-E. ;. 



Munidopsis Whiteaves ; Galathodes A. M.-E. ; Elasmonotus A. M.-E. 



Fam. 4. Poreellanidae. Rostrum short and broad or 0. Scale of 2nd 



antenna 0. Abdomen bent and applied to thorax as in Brachyura, but 



with a small swimming fan. Some 6 genera, all littoral ; under stones 



between tide marks. Petrolisthes Stimps. ; Pachycheles Stimps. 11 spp. 



chiefly tropical. Porcellana Lmck. Cephalo-thorax longer than broad ; 



larva with very long rostral and posterolateral spines. 20 or 30 spp. widely 



distributed. P. platycheles (Pennant) and P. longicornis (L.) common 



under stones round our shores. Megalobrachium Stps. and Polyonyx 



Stps. live a semi-parasitic life in sponges, the mollusc Aspergillum, etc. 



Warm seas. Eaphidopus Stps. 



Tribe 4. HIPPIDEA. 



Shallow-water forms living buried in sand. The body is nearly cylin- 

 drical, and the abdomen is loosely folded under the thorax. Other 

 characters are noted above (p. 537). 



Fam. 1. Hippidae. Sand crabs. Carapace ovate or subquadrate, 

 overlapping the bases of the legs ; thoracic sterna linear ; eyes with 

 small corneae ; 1st antenna with 1 long flagellum ; 2nd with massive 

 base ; 3rd maxillipeds suboperculiform, without exopodite ; 1st trunk- 

 legs not chelate, 5th filiform; abdomen partly extended, with long 

 lanceolate telson, 6th appendages large and lamellar, adapted not for 

 swimming but for digging as the animal buries itself, backwards, in the 

 sand. Hippa hatches as a zoaea with 2 pairs of maxillipeds, and very 

 long rostrum. Hippa Fabr. 2nd antennae with long curved flagella,. 

 mandibles functionless, and fused with the adjacent parts of the shell ; 

 first abdominal segment fused with thorax. H. eremita (L.) live in great 

 numbers on sandy shores of the eastern United States, near low tide level ^ 

 and burrow with great rapidity. They apparently live, after the manner 

 of earthworms, on the organic matter contained in the sand, which they 

 swallow in large quantities (Smith). Remipes Latr. 2nd antenna with 

 short flagellum. Mastigochirus Miers, first trunk-legs flagelliform. 



Fam. 2. Albuneidae. Resemble the last family, but 3rd maxillipeds 

 are subpediform, with exopodite, and first trunk-legs are chelate ; cara- 

 pace flattened, but not overlapping the bases of the legs, excavated for 

 reception of 1st abdominal segment ; telson ovate. Albunea Fabr. 

 Mediterranean, Celebes, first antennae form, when in apposition, a channel 

 for the respiratory water. Blepharipoda Randall. 



Section 4. BRACHYURA. 



The carapace is broad and longer than the short abdomen. 

 The latter is without a caudal fin, is bent forwards and applied to 



