﻿COPEPODA -j-i^ 



[C/i. ahyssalis ^nd p/isf/i/i/rra). Conc.si)(Muiiiio; to the difference between the mature females and males 

 a difference is sometimes found l)et\veen tlie two sexes in the penultimate sta<^e; in Gaidius tcnuispi- 

 js/is and Eiichirclla roslrahi f. inst. the young female has along the inner margin of the second hasi- 

 podite in the fourth pair of legs a few lamellous setae, while the young male has a few of usual 

 structure; in most species of Eiicliir,lla and Chintdiiiti the margin is smooth in both sexes in the 

 penultimate stage. 



The Act id ins is a well characterized genus which, as far as can be concluded from the wanting 

 glandular pore in Re I pes II and the well developed marginal setae in the fourth pair of legs, is a 

 rather primiti\e form. The Chiridius, to which genus I refer not only Cli. obtiisifroiis without distinct 

 rostrum, but also C/i. ani/afits in similarit\- to ,Sars and in contrast to Vanhoffen and Wolfenden. 

 is among other features characterized b\- the wanting plate-shaped process of the secijud basipodite of 

 the maxillipeds, the well developed exo[)odite of the first pair of legs with 3 setae, and the slender 

 marginal setae of the fourth pair of legs; as Giesbrecht had originally established the genus for a 

 species without rostrum, Wolfenden and Vanhoffen have accepted the name Pscudoaetidins for 

 Ch. aniiatus\ vSars has judged this single character as being of minor importance, and he is certainly 

 right, especially when it is taken into consideration that a rudimentary slightly bifurcate rostrum is really 

 found. On account of the great number of glandular pores in the three last pair of legs (PI. II figs. 

 3— 5a) I once thought that Wolfenden was right; but as Cli. luudcstns n. sp., which in other respects 

 was like Cli. aniiatiis, has 3 glandular pores (including one in Re I), 1 definitive!)- accepted vSars' 

 definition. .Sars has established a new genus ^-Efidiopsis synonymous with Wo 1 fend ens Facroclla, 

 especial!)' characterized by well develo^Ded fiftli tlioracic tergite; as a fairl\- well marked fifth somite 

 is found in most specimens of C/i. anna //is, I do not tliink this genus is a good one. A.Scott's new 

 genus Gaidiopsis (1909 p. 52), characterized by a very robust rostrum, is probab!\' nearl\- related to 

 C/iirfdiiis. 



The genera Bradyetcs Farr. and Uiidinopsis G. O. Sars (synonymous with Bradyidiiis Giesbr.) 

 are nearly related; Pscndocucha-lc Sars is according to Far ran related to tliese genera as well as to 

 Bryaxis lioeck, the position of wliich seems to be a little doul)tful on account of the poorl\' developed 

 outer ramus of the antennae. The position of Sars' genus Chiridicllu is \-ery doubtful. I ha\-e not 

 liad the opportunity of examining au)' specimens of tlie last mentioned five genera. 



According to Giesbrecht (1S92 p. 241)) tlie genus Gaidius has "rostrum kurz einspitzig" 

 and "Aussenast des ersten Fusses zwei . . . und Innenast des i. uud 2. Fusses eingliedrig" and the only 

 difference from Gar/aiuis is found in tlie frontal spine and the two-sc.-giuented eiidopodite of the second 

 pair of legs of the latter genus. The cliaracter found in the segmentation of the eiidopodite 

 of the second pair of legs is not of much value, as this articulation is well developed m 

 mos,t species of Gaclaiiits as well as in Gtirdius brcvispifiiis, sliglith' developed in Gactaiius iiiilis and 

 Gaidius leiiuispiiius. and completeh' wanting in Gaetanus minor. Tlie presence or absence of tlie frontal 

 spine seems to me to furnisli a good s])ecific, l^ut scarcely a generic, character; .Sars seems to share 

 this opinion, as lie has estal)lis!ied a C/^/cA/;///.v ///(Vw/> without ain- spine. \A'olfenden has established 

 a new genus Mrsogaidius (191 1 p. 223) for liis AI. iufcrn/idius, perhaps identical with G. brc'ispiuus, and 

 his i]/. iiiaxiii/iis, because they combine tlie wanting frontal .si)iiie with "das \'orhandeuscin eines Zipfel 



Ihc IiiHolf-lixpiJiiiuii. III. 4. 10 



