ARTHROPODA 



205 



and in rotting wood, they are shy and nocturnal in habit with a marked 

 dishke of hght. They are beautiful, velvety, caterpillar-like creatures 

 with paired eyes set like diamonds (0- 2 to 0- 3 mm. ) on the side of the head 

 behind the two sensitive antenna?, looking upwards and outwards, not 

 forwards (Fig. 197) ; the eyes, like those of marine Polychsetes, are of 



Figs. 



198 TO 200. — The Eyes of the Large Crustaceans (Decapods) 

 (Specimens from Natural History Museum, London). 



Fig. 199. 





Fig. 198. 



Fig. 200. 



Fig. 198. — The common shrimp, Crangon vulgaris. The short eye-stalks 

 bearing the compound eyes lie in sockets in the carapace. 



Fig. 199. — The fiddler crab, Gelasimus arcuatus. There are two com- 

 pound eyes, C, each standing out prominently on a muscular eye-stalk and 

 protruding on either side of the median rostrum. The left claw is repi-esented 

 by a small stump ; the huge right claw gives the animal its name. 



Fig. 200. — The racing crab, Ocyilpoda ippens. Two j^rominent elongated 

 compound ejes, C, are set on eye-stalks, in sockets on the carapace. 



