MALACOSTRACA., 309 
Sub-order Macrura.—Abdomen long. Homarus (lobster) ; Meph- 
vops (Norway lobster, sea crayfish); As¢acus (fresh-water crayfish) ; 
Palinurus (rock lobster), whose larva was long known as the glass- 
crab (Phyllosoma) ; Peneus, a shrimp which passes through Nauplius, . 
Zoza, and Mysis stages ; Lucéfer and Sergestes are also hatched at a 
stage antecedent to the Zoza 3; Crangon vulgaris (the British shrimp) ; 
Palemon, Pandalus, Hippolyte (prawns); Galathea (with the abdomen 
Fic. 163.—Hermit-crab withdrawn from its shell. 
The anterior appendages are broken off. 
hd., Head; ¢., thorax ; aéd., abdomen. 
bent forwards) ; Pagurus, Eupagurus (hermit-crabs) ; Bzrgus latro (the 
terrestrial robber or palm-crab), in which the upper part of the gill- 
cavity is shut off to form a “‘lung,”.the walls having numerous 
vascular plaits. ; 
Sub-order Brachyura. — Abdomen short, and bent under the 
thorax. It is narrow in the male, and does not usually bear more 
than two pairs of appendages; it is broader in the female, and 
bears four paired appendages. The ventral ganglia have fused 
