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I regard this species to be more closely related to the one originally illustrated in the 

 'Challenger' report as ^Etideus armatus, than to the species now known as sEtideus armatus 

 (Boeck). The very strong rostrum described and figured by Brady, is a character not possessed 

 by Boeck's species. The last thoracic spines in the 'Challenger' specimen, appear to have been 

 shorter than in the present form, but I have noticed, that these chitinized spines are easily 

 damaged, ancl perfect specimens with the spines complete, may not always be secnred. With 

 regard to the specimens from the 'Challenger' collection examined by Sars, and stated to be 

 identical with Boeck's species: — It is quite possible, that more than one type of ALtideus 

 was obtained by the 'Challenger', but the difterences were not regarded as worthy of specific 

 rank at that time, and the type from which Brady's figures were drawn, might easily be 

 distinct from those examined by Sars. I have found on re-examining the selected specimens 

 from the Gulf of Guinea plankton, regarded to be identical with the type described in the 

 'Challenger' report, that all the three forms now figured were present. jEtideus giesbrcchti '. 

 and the lorm now described as ^Etideus brady i, proved, on the re-examination of the selected 

 specimens, to have been present in the plankton collected by Professor Herdman, on the way 

 out to Ceylon. 



Wolfexdex (1903, p. 266) refers to a species, ^~Et. bradyi (Brady), but I am unable to 

 identify it. Brady has not named a species of jEtideus after himself. 



Genus Bradyidius Giesbrecht, 1897. 



This genus is closely related to JEtideus, but differs from it in the less highly developed 

 rostrum, and by the endopodite of the second pair of swimming feet being distinctly two-jointed. 



One species belonging- to this genus was found in the plankton collected during the 

 traverse of the 'Siboga'. The specimens differ in some minor details from Sars figures of the 

 northern type but, I have, for the present, decided to regard them as simply tropical examples 

 of Bradyidius armatus. 



1. Bradyidius armatus (Brady). Plate VI, figs. 1 — 11. 



P seudocalanus armatus Brady, 1878, non Boeck 1872, Vol. 1, p. 46, pi. IV. 



Undïnopsis bradyi Sars, 1884 (name only). 



Bradyanus armatus Vanhoften, 1897, p. 322. 



Bradyidius armatus Giesbrecht & Schmeil, 1898, p. 32. 



Bradyidius armatus T. Scott, 1898, p. 264, pi. XII, figs. I — 19. 



Bradyidius armatus T. Scott, 1899, p. 248. 



Bradyidius armatus I. C. Thompson, 1900, p. 278. 



Bradyidius armatus T. Scott, 1900, p. 383. 



Bradyidius armatus T. Scott, 1901, p. 238. 



Bradyidius armatus T. Scott, 1901 (a), p. 350. 



Undinopsis bradyi Sars, 1902, p. 32, pis. XIX & XX. 



Bradyidius armatus I. C. Thompson, 1903, p. 16. 



Bradyidius armatus Wolfenden, 1904, p. 111. 



Bradyidius armatus Wolfenden, 1905 (a), p. 1005. 



Bradyidius armatus Farran, 1905, p. 31. 



Bradyidius armatus Pearson, 1906, p. II. 



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