TEM0EA. 55 



movable hinge between the eighteenth and nineteenth 

 joints, the last four joints being very long and 

 apparently representing a coalescence of eight joints ; 

 the inner margins of the joints immediately above and 

 below the hinge are armed with finely denticulated 

 plates ; and the fourteenth to the eighteenth joints 

 (both inclusive) are swollen, apparently to give more 

 space for the powerful muscles by which the organ is 

 moved. The posterior antennae and the mouth-organs 

 do not differ materially from those which have been 

 already described. Inner branches of the first four pairs 

 of swimming feet two-jointed; those of the first 

 pair often apparently one-jointed owing to imperfect 

 division. The fifth foot in the female (fig. 16) consists 

 of a simple, cylindrical, and rather stout three-jointed 

 branch, the last joint being the longest and having 

 two small lateral, and two apical spines of about equal 

 size. The right fifth foot in the male (fig. 17) consists 

 of a large basal joint to which are articulated two 

 opposable claws, one of these being long, simple and 

 curved, the other composed of two broader joints, and 

 bearing at the apex two tooth-like spines and two 

 short hairs : the left foot is three-jointed, subchelate, 

 but unbranched. The terminal spines of the swimming 

 feet (fig. 19) are long and straight, with slightly 

 curved apex and finely serrated inner border. The 

 caudal segments (fig. 18) are extremely long and 

 slender, quite equal in length to the whole of the 

 abdomen, about eight or nine times as long as broad, 

 and bearing a single short lateral spine on the 

 external margin, about half way between the middle 



