460 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. xxxm. 



that in Pandarus. Rami of fourth legs one-jointed, of all the others 

 two-jointed. 



They give Nogagus hrevicaudatus , IMilne Edwards, as a synonym 

 of this species and say that it is probable when it becomes better 

 known it will be found identical with tenax. They then add in 

 closing : 



Since N. tenax is smaller than N. borealis, and is found fartli(>r south in the Atlantic, 

 it would seem probable that it is the male of the smaller and more southern Dinematura 

 described by us, D. latifolia. Still this is nothing more than a conjecture. 



It has already been shown in the present ])aper (see p. 449) that 

 the morphologA^ of Nogagus horealis renders it probable that it is a 

 Nesipjms male rather than one of the genus Dinematura. 



Moreover, there will be found described on page 386 the true male 

 of Dinematura latifolia which is very different from the two species 

 here mentioned. Nogagus tenax therefore is probably a Nesippus 

 male, and so far as can be seen is identical with the one described 

 on page 429 as the male of Nesippus alatus. There are slight differ- 

 ences in the angularity of the thoracic segments of tenax and the 

 rounded outlines of alatus, but Steenstrup and Ltitken's material had 

 been in alcohol a long time, while the drawings in the present paper 

 were made from living males. 



Furthermore, this same species (tenax) has been reported by S. I. 

 Smith upon Atwood's shark (Carcharias atiroodi) in Vine^^ard Sound. 

 It was found in company with " Nogagus latreillii," a species of Pan- 

 darus, and Echthrogaleus denticulatus . Smith recognized that it was 

 very different from N. latreillii and probably belonged to a different^ 

 genus. He suggested Echthrogaleus, but the structure of the second 

 and third legs prohibits this. No specimens of Nesippus alatus 

 females have yet been obtained from Atwood's shark, but they are 

 so common in Vineyard Sound on other sharks that the presence of 

 a free swimming male on this particular species can be readilj^ 

 understood. 



Again tenax is represented with small sharp spines near the pos- 

 terior corners of the genital segment; similar specimens have been 

 found among the males of alatus, but the outlines given in fig. 206 are 

 more common. In all other particulars the two are practically 

 identical, and accordingly Nogagus tenax has been given as a synonym 

 under Nesippus alatus (see p. 426). 



PANDARUS UNICOLOR (Nogaus male) Hesse. 



Pandarus unicolor Hesse, 1883, p. 20, pi. vi, fig. 5. 



This species was described in the same paper with Pandarus 

 musteli-lsevis and Nogagus spinacii-achantias and in a similar manner. 

 The discrepancies in the appendages of the male are similar to those 

 enumerated for the other species, but here the swimming legs are 



