596 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. xxxiii. 



maxillipeds armed with a long and stout spine which overlaps the tip 

 of the terminal claw. Body of the semen receptacles in the genital 

 segment of medium size, situated close to the posterior margin of the 

 segment, with a tube running the whole length of the segment and 

 intricately convoluted. Fifth legs visible dorsally and appearing on 

 the lateral margins of the genital segment about one-third the distance 

 from its posterior end. 



Total length, 2.2 mm. ; carapace, 1.2 mm. ; genital segment, 0.5 mm.; 

 abdomen, 0.4 mm.; width of carapace, 1.1 mm. 



Color of both sexes a uniform yellowish pink, thickly penciled on 

 both the dorsal and ventral surfaces of the body and the two median 

 pairs of swimming legs with spots and lines of a bright rust-colored 

 pigment. The eyes are exceptionally clear, so clear in fact that they 

 stand out plainly to the naked eye in spite of the minute size of the 

 copepod. They are assisted in this by their deep reddish-brown color, 

 which contrasts strongly with the pink of the body. 



The species is readily distinguished by these large eyes and by the 

 absence of any plumose setae on the first swimming legs. 



(Jixmulonis, the generic name of their host.) 



Several males and females of this species were obtained, some from 

 the mouth of the blackiish, Centropristes striatus, others from the 

 mouth of the catfish, Ilexanematiclithys felis and still others from the 

 mouth of the seacat, FelicJithys 7narinus. Those from the blackfish 

 are Cat. No. 32816, U. S. N. M. collection, those from the catfish are 

 Cat. No. 32815, U. S. N. M., and those from the seacat, Cat. No. 

 32813, U. S. N. M. 



Kroyer obtained only three specimens, two females and a male, all 

 from Ilsemulon elegans Cuvier in the Danish West Indies. 



The finding of the present specimens, therefore, adds three new hosts 

 and extends the habitat of the species well up along the Atlantic 

 coast. There can be no doubt that this is Kroyer's species, since it 

 agrees in every essential particular with the description he has given 

 except in the shape of the frontal plates and the genital segment. 

 With reference to the latter it is enough to say that the females 

 obtained by the present author were smaller (and younger?) than the 

 one whose dimensions he has given. And the discrepancy is no 

 greater than would ordinarily be expected between such different 

 stages of maturity. 



In regard to the projecting frontal plates the case is different. 

 Kroyer had two females which presumably agreed in this particular, 

 but they had both been preserved for some time while the present 

 specimens were examined while alive. 



We can only conclude that the absence of plumose setae on the first 

 legs is of more specific value than the shape of the frontal plates. 



With reference to the habits of the species it may be said that their 

 activity is in inverse ratio to their size. Both sexes, but particularly 



