NO. 1573. PARASITIC COPEPODS— WILSON. 459 



None of the known species of Pandarus has any sucli a prehensile 

 apparatus as this, nor is there any genus of Crustacea in which the 

 fu'st legs have disappeared, leaving the other tlu'ee present and 

 fully developed. If this structure be as Hesse has represented it, 

 his specimens will have to be made the t}^es of a new geims. But 

 again he is consistent, for, in speaking of the new Nogaus, after 

 describing the second maxillipeds which he calls the "third thoracic 

 feet," he says: 



Au-dessous de celles-ci on apercoit, placee horizontaleinent, line patte tres etroile 

 fixee par son centre au bouclier cephalique et terminee a son extremite par deux 

 petits articles, dont le dernier est recourbe en forme de griffe. 



This evidently corresponds to the fixation apparatus of the female 

 and makes the analogy between the appendages just what woidd 

 be expected in the two sexes of a species. 



Finally the general make-up of the body in this Nogaus is similar 

 to that in the Pandarus males. There is the same broad carapace 

 with what are evidently accessory posterior lobes, partially con- 

 cealing the second segment; a considerably enlarged genital segment 

 with large posterior processes, and a two-jointed abdomen with good 

 sized anal laminne. There is thus considerable probability that we 

 have here the two sexes of a species of Pandarus: whether it is a 

 new species can not be determined without further data. 



Hesse begins his description of the Pandarus species with the 

 words "Male inconnu" (p. 10), but further along (p. 15), and in 

 ^his figures (Plate VI, fig. 9) he has presented what he calls a "jeune 

 male ( ?)." If this were really a young male of the species in question, 

 it ought to correspond with other Pandarus males. But no details 

 9,re given in the text, and those to be deduced from the figure are 

 decidedly against the probability that the creature belongs to the 

 genus Pandarus. 



NOGAGUS TENAX, Steenstrup and Liitken. 

 Nogagus tenax Steenstrup and LDtken, 1861, p. 388, pi. x, fig. 20. 



This species was described by the above authors as follows: It 

 outwardly resembles Nogagus horealis, but is smaller (6 nun. long), 

 and less elongate; eyes distinct and near the anterior border. First 

 free thorax segment broadly quadrangular with wide lateral lobes; 

 the second one smaller and somewhat six-sided; the third the 

 smallest and broadly eight-sided. 



Genital segment not much longer than wide, the posterior corners 

 projecting slightly and armed with spines. Abdomen triangular 

 and bearing triangular anal laminae. Second maxillipeds some- 

 times showing an end claw and sometimes a forceps structure like 



