COPEPODA 



77 



itnens which they have referred to A. armatus are not to be distingxiished from specimens from the 

 northern seas. The gulf of Guinea, the South Atlantic, the Indian and Malayan Seas ought accor- 

 dingly to be regarded as lying within the range of this species. Even if Sars is right, that some 

 of Brady's specimens are identical with Boeck's species, we are not right in concluding that the 

 species has the distribution stated by Brady (cf. A. Scott's remark p. 37). 



16. Chiridius armatus Boeck. 

 (PI. II figs. 3a e; text-figs. 17 a d). 



1872. Ruchaete arniata n. sp. Boeck, p. 39. 



1897. nee. Pseudocalanus armatus Boeck. Vanhoffeu, p. 279, 



fig. 1 6. 



1900. nee. Chiridius armatus Boeck. G. O. Sars, pp. 2930. 

 1903. -^ G. O. Sars, pp. 27 29, 



pis. XV XVI. 



1903. Jensen, Johausen & Le- 



vinsen, p. 304. 



1904. Pseudoaetidius armatus Boeck. Wolfenden, pp. 115 



and 131, pi. IV figs. 29 31. 



1905. Chiridius armatus Boeck. Farran, p. 34. 

 1905. G. O. Sars, p. 2. 



1905. Th. Scott, p. 222. 



1906. Pseudoaetidius armatus Boeck. Pearson, p. u. 



1907. Chiridius armatus Boeck. Koefoed & Damas, p. 408. 



1908. Farran, p. 30. 



1908. Pseudoaetidius armatus Boeck. v. Bremen, p. 33, 



fig. 34- 



1911. Chiridius armatus Boeck. Farran, pp. 90 91. 



1913. nee Stephensen, p. 316. 



Description. f$. Size of specimens from Thor St. 172 measured 4-43 mm., anterior division 

 3-3 mm., urosome no mm. The smallest specimen (Thor St. 72) measured 3-6 mm. 



The body differred in the following features from Sars' description; laterally and beneath, the 

 limitation between the head and first thoracic tergite is indicated; the fifth thoracic tergite, which is 

 produced into well developed triangular points, is 

 short, but well distinguished (text-fig. 17 c). The 

 genital somite is only slightly produced beneath, and 

 the receptaculum has, as seen in fig. 17 d, a charac- 

 teristic structure. The furcal rami, which are a little 

 longer than the anal somite, are scarcely 1-3 as long 

 as wide. 



The antennulae, which have the segment 25 

 well marked out with rather indistinct articular 

 membrane, have the segment 2 a little longer than 



8 <N> 9, which is as long as the segment 20; the seg- 

 ment 21 is a little longer than 18, and the segment 

 23 is distinctly ri as long as 24. The arrangement 

 of the appendages is scarcely different from that of Ch. 



obtusifrons; the posterior seta of the segment 23 just Text-fig. 17. Chiridius armatus Boeck. 



a. Head in dorsal view X 16. b. Head in lateral view X 6- 

 reaches the tip of the Segment 25. The exopodite c. First abdominal somite in dorsal view X 50. 



of the antennae is scarcely 1-4 as long as the endo- d ' Lat , eral co er etc ' x ^ e " Parasite attached to the 



right maxilla X 74- 



podite. The Le i of the maxillulae has as usual 



9 setae and the Li 2 possess 5 spinelike setae, the Li 3, which terminally on the anterior surface has a 

 curved row of short spines, has 4 setae, and the basipodite III has a similar row of short spines and 



