WILSON, FARASITIC COPEPODS FROM JAPAN. 7 



around a deeply sunken pit. The first antennae lie along 

 tlie anterior portion of this margin and just outside the 

 base of each a stout hook or claw projects into the cavity 

 of the pit. The first legs curve around the posterior portion 

 of the margin, the two rami projecting outwardly. 



The cephalothorax is transversely elliptical in dorsal 

 outhne, one-fifth wider than long, with evenly rounded mar- 

 gins. The thorax segments diminish regularly in width from 

 the second to the fifth and entirel}^ conceal the legs in dor- 

 sal view, except the fifth pair. 



The genital segment is considerably narrower than the 

 anterior portion of the fifth segment, but about the same 

 width as the posterior portion; it is as wide as long and 

 squarely truncated at either end. 



The abdomen is composed of four segments, diminishing 

 regularly in size backwards, except that the last one, though 

 narrower than the others, is a trifle longer. The anal laminae 

 are narrow, two-thirds the length of the last segment, each 

 tipped with two long setae and having two shorter ones on 

 the outer margin. The egg cases are attached to the dorsal 

 surface of the genital segment; each is considerably wider 

 than the genital segment itself and more than half the en- 

 tire body length. The eggs are mumerous, arranged in ten 

 or twelve rows, about 35 eggs in a row. 



The basal portion of the first antennae is not much en- 

 larged and is indistinctly divided into three parts, with a 

 row of large flattened setae along its anterior margin. The 

 terminal portion is made up of three distinct segments, 

 heavily armed with smaller setae. The second antennae are 

 three-jointed and tipped with three long curved claws, with 

 two others on the dorsal margin of the terminal joint. 



The anterior ventral surface of the cephalothorax is 

 deeply reentrant, forming a sunken pit, upon whose ante- 

 rior walls are located the second antennae and mouth parts, 

 except the maxillipeds which are on the posterior walls. 

 None of these appendages is visible until the pit has been 

 cut out of the cephalothorax, slit down its sides, and then 

 flattened out under a cover glass. 



The upper lip is orbicular, about the same width and 

 length, with a prominent knob on either side at the base. 

 The mandibles are three-jointed, the two distal joints bent 



