25 (24) Abdomen well developed, symmetrical or asymmetrical 26 



25 (24) Abdomen reduced in size, symmetrical and flexed under thorax 



Superfamily Hippidea, Family Hippidae. Emerita talpoida. mole crab 



Figure 48. — Emerila talpoida, lateral view. 



26 (25) Abdomen symmetrical (or superficially so), more or less flexed beneath thorax; thorax 



depressed and crablike Superfamily Galatheidea 27 



26 (25) Abdomen asymmetrical, tail fan reduced and adapted for holding body in mollusk 



shells Superfamily Paguroidea, Family Paguridae, Pagunis. hermit crabs A 



A (26) Palm of small (left) chela roughly oval in cross section, upper surface flattened, 



not divided by a ridge B 



A (26) Palm of small (left) chela triangular in cross section, upper surface divided by 



longitudinal ridge into 2 obliquely sloping facets E 



Figure 49. — Cross sections of pagurid palm 

 (propodus); A, oval; B, triangular. 



B (A) Cornea of eye dilated, length of eyestalks not more than 3.5 times greatest width C 



B (A) Cornea not dilated, length of eyestalks at least 4 times greatest width (small 



species) P. annulipes 



Figure ."^O. — Panunis annulipes: A, anterior part of 

 body; B. chelae and carpi, dorsal views. 



18 



