3232 



THE JOINTED ANIMALS 



pressed and has a small rostrum, but the abdomen is well developed and often wider 

 in the middle than in front. As in the short-tailed group, the fourth pair of thoracic 

 limbs are enlarged and generally completely chelate, while the four succeeding 



pairs, of which the last is 

 smaller than, the rest, usually 

 terminate in simple claws. All 

 the members of this group are 

 exclusively marine, living at 

 the bottom of the sea buried a 

 foot or more in the mud. The 

 figure on p. 3231 represents 

 a species ( Thaumastocheles 

 zeleuca) obtained at a depth of 

 four hundred fathoms in the 

 West Indies. It is character- 

 ized by the extraordinary de- 

 velopment of the pincers of 

 the right claw, which are not 

 only very long and slender but 

 LARVA OF CRAWFISH, THE SO-CALLED GLASS-CRAB. beset with spine-like teeth. The 

 (Natural size.) creature is totally blind, having 



lost both eyes and eyestalks. 



In the tribe of the Scyllaridea none of the limbs of the thorax are truly chelate, 

 and the antennae are not furnished with an external scale-like basal piece. The 

 best-known members of this group are the Palinuridce, or rock lobsters, one member 



SLENDER-CLAWED CRAWFISH, Willemczsia leptodactyla. 

 (Natural size.) 



