NO. 2274. A NEW PARASITIC COPEPOD— WILSON. 3^5 



Of the month parts the inaxiUary hooks are somewhat smaller and 

 shorter than those of the female; the maxillae are also smaller and 

 the endopod is reduced so much as to be scarcely discernible. The 

 furca i'^ of the same general pattern, but the lateral branches are more 

 slender and are directed diagonally backwards instead of standing 

 out at right angles. 



The swimming legs are similar to those of the female, except that 

 the claws on the fourth pair are slightly enlarged. 



Color (preserved material) a dark purplish red, deepened along 

 the ribs and in the appendages. 



Total length — female, 12.50 mm. ; male, 10.50 mm. Length of 

 carapace — female, 5.85 mm. ; male. 4.06. Width of carapace — fe- 

 male, 5.50 mm.: male, 4 mm. Width of genital segment — female, 3 

 mm. ; male, 1.95 mm. 



{costatus, ribbed, alluding to the supporting ribs of the carapace.) 



Remarks. — The m.ale here described corresponds closely with the 

 one presented by Stebbing' and is not at all like the one figured and 

 described by Thomson.^ This renders it even more probable that 

 Thomson's specimens were both females — one with and the other 

 without egg strings. The present species differs from ornatus in 

 the dimensions of the carapace, in the size and shape of the dorsal 

 plates on the fourth segment, in the length of the posterior lobes of 

 the geital segment compared with the abdomen, and in the relative 

 size of the latter, 



SPECILLIGUS versas NESIPPUS. 



In the Proceedings of the United States National Museum (vol. 

 33, p. 434), a parasitic copepod described by Dana under the name 

 SpecilJigus curticaudis was referred to the genus Nesippus. Dana's 

 description was published in 1852, while the genus Nesippus was not 

 founded until 1865 by Heller. Apparently Heller's genus should be 

 made a synonym of Dana's instead of the reverse, and some writers 

 have already done this, supposedly believing that the two had been 

 proved to be identical. Such a proceeding did not seem wise at the 

 time above referred to, and seems even less so to-day, for the fol- 

 lowing reasons : 



Dana's genus was founded upon one or two specimens, all of the 

 male sex and unfortunately long since lost. His establishmimt of a 

 new genus upon male specimens alone was not valid, because they 

 properly belonged in the genus Nogaus as it then stood. There was 

 no reason for separating them as a distinct genus, and such a reason 

 could only be found in the structure of the females. But Dana 

 possessed no female specimens and none have since been discovered, 

 so that the genus still remains incapable of being justified. All the 



* Willey'B Zoological Results, pt. 5, 1900, p. 671, pi. 74, fig. A. 

 » Trans. New Zealand., vol. 22, 1889, p. 354, pi. 29, fig. la. 



