NO. 1580. NEW SPECIES OF C ALIO IN.E— WILSON. 617 



The female can not swim, nor does she move about ordinarily on the 

 body of the host, but remains fixed in one place. 



The male, on the other hand, can swim a little and contrives to wrig;- 

 gie about over the fish's skin by a sort of jump-aiid-catch method, 

 using the second maxillipeds and swimming legs. 



Both sexes, when placed in an aquarium, lie most of the time upon 

 their backs, with the swimming legs vibrating rapidly l^ack and forth 

 like the abdominal appendages of the Phyllopods. But in the present 

 instance this is probably not a respiratory movement, for even the 

 adults show distinctly the set of muscles used for cloacal respiration, 

 as already described in other genera. The females have also the habit 

 of raising the carapace or bending it to one side till it stands nearly at 

 right angles to the rest of the body, the flexure taking place between 

 the carapace and the genital segment. So constantly is this practiced 

 that it is difficult to get one killed with the body straight. There is 

 also more or less folding and unfolding of the sides of the carapace, 

 very different from Lemanihropus , in which the carapace sides seem 

 incapable of much voluntary motion. 



TUXOPHORUS, new genus. 



Genus diagnosis. — First three thorax segments united with the 

 head and covered by a shield-shaped carapace. Frontal plates promi- 

 nent and furnished with lunules as in Caligus. Eyes small with promi- 

 nent lenses. Second antenme small and weak. Second maxillfe 

 articulate at the base, the rudimentary endopod borne on the basal joint. 

 Th^ other mouth parts and the mouth tube as in Caligus. Furca com- 

 pound, its terminal branches ])ifid. Swimming legs as in Caligus. 



Free segment short and wide, covered by two dorsal plates, which 

 overlap the genital segment and project outward over the bases of the 

 fourth legs. Genital segment enlargetl, without plates or processes. 

 Abdomen narrow, one-jointed; anal laminte large and well armed 

 wdth seta?. Egg tubes wider than the abdomen and nearl}^ as long 

 as the entire body. Eggs and development as in Caligus. 



Type of genus. — Tuxopliorus callgodes. 



(tuxophorus, TTTV^, a plate and (f>opeoj to bear.) 



TUXOPHORUS CALIGODES, new species. 

 Plate LV and Plate LVI, ligs. 93-99. 



Types.— Cat. No. 32805, U. S. National Museum. 



Female. — Carapace ovate, narrowed but little anteriorly, as wide as 

 long, and about half the entire length. Frontal plates prominent and 

 furnished v,'ith large hemispherical lunules similar to those on Caligus. 

 These lunules are widely separated and project hardly at all from the 

 anterior margin. Posterior sinuses narrow and shallow; median lobe 

 a little less than half the entire width, projecting only a trifle beyond 

 the lateral lobes and quite squarely truncated posteriorly with promi- 



