XEMATORRACHIOX. 265 



third, rather abruptly lieiit upwards, at a httle distance from its base; ])efore 

 this cur\'ature its upper edge is pr()(hic(>d into a flat, vertical j:)late and at a short 

 distance from tlie curvature the joint is again somewhat bent, but in the opposite 

 direction and thus directed foi'wards; seventh joint two thirds to three fourths 

 as long as the sixth, at the end with six closely set, long, serrate, stiff but thin 

 spines, fovu' of those projecting from the end, two from the side a little from 

 the end. Third to tiflli pairs of legs with tlie shape antl relative length of the 

 joints in the main as in Thysanopoda. Sixth ])air of legs with the full number of 

 joints in the somewhat short endopod and the exopod is well developed. Se\'entli 

 pair with a normally developed, sometimes small exopod, wliile an endo])od is 

 not developed, the exopod-bearing joint terminating in a short, broad lobe with 

 some .setae. — Branchiae nearly as in Nematoscelis. — Preanal spine simple 

 in the male, simple or bifid in the female. — Luminous organs as in Thj^sanopoda, 

 etc. 



The copulatory organs of first jileopods in the main as in Thysanopoda, 

 with all lobes and fi\'e j:)rocesses well develojjed. — No female with o\-isacs has 

 been found. 



RoNdfks. — This interesting genus was founded by Dr. Caiman on a single 

 specimen of a new species; he nametl it Xonatiiddiii/Ius Imnpis, and coi'rectly 

 referred Sti/lochciwn flexipes Ortm. to the same genus without ha\'ing seen any 

 specimen. Later Caiman obtained a little more material, among which a muti- 

 lated male, of iV. boopis and then lie published additions and corrections to 

 his earlier statements and changetl the name of the genus to Nematobrachion, 

 as the former name was i)reoccu]ned. Caiman's account of the genus and of his 

 single species is \Try good, but as he has examined only one species, while I 

 possess three species, ami as the interesting sexual diffei'ences in antennulac 

 ami the sixth jiair of thoi-acic legs in the other genei'a with dixided eyes were 

 then nearly unknown, I ha\'e thought it useful to give h(>re a descrijition of 

 tlie genus. I must add that in l'.)().") I i-efei'red SIi/IocIk iran Jlrriptx Oi'tm. to the 

 present genus, luiving o\'erlooked that this hatl alreatly been done ijy Caiman 

 in 1896. 



According to some remarks in I'.IO.") Caiman has felt the difficulty as to the 

 relationshi]is of Nematobrachion and the tliree other genera with di\ided ryes 

 and one i)air of ])rehensile legs; in mentioning the two postcM'ior pairs of thoracic 

 legs he cori'ectl>' jiointed out their resemblance with 'I'hysanopuda, and he states 

 that the copulatory organs of first ])leopods are "much more complex" than in 

 Stylocheiron or Nematoscelis. Nematobrachion occupies in r<'ality a \'ery 



