18 R. NORRIS WOT.FRNDEN. 



Giesljrecht's species E. diistrinn, though I have fouiid it in the ' Gauss ' collections. 

 E. antarcfica appears in many stages, extensive captures consisted wholly of 

 immature specimens, ])ut there are many adult examples. Many males appear amongst 

 these, and while the females are very distinctively different, I am not aljle to discrimin- 

 ate l)et\veen those males, as to which definitely belong to (intarctiat, and others 

 which mio'ht belong to shin/ is. Both species are very closely allied, and difter 

 very considerably from tlie large species of the northern cold seas, viz., nonm/ica, 

 glacialis and linrhntii. 



EUCHAETA ANTARCTICA. 

 (Plate I \'., tigs. .5, (I.) 

 Euclueta antarclka, GicsbrccLt, ' Belgica' Report, p. 21. 



This is one of the most abundant copepods in the ' Discovery ' collection, appearing 

 in all stao-es of growth, and in some samples almost to the exclusion of other species. 



Size of adult examples 7 • 6 mm.-8 mm. Head evenly rounded, without frontal 

 prominence and with short rostrum directed forwards. Last thoracic segment with 

 rounded margins, produced forwards and with a bunch of liairs on each side. The 

 abdominal segments have the postero-distal margins armed witli rather strong l)luntly 

 conical and striated teeth, and the two middle segments have on the ventral side 

 bunches of long hairs. The furca and bristles are the same as in E. similis. The 

 genital protul)erauce occupies the lower half of the segment, its upper margin is not 

 deeply concave like similis, Init the whole swelling is directed downwards, and its upper 

 maro-in is slightly convex. Above the genital swelling is a secondary prominence, 

 which in the ventral aspect is seen to consist of two valve-like chitin thickenings. The 

 lower part of the protuberance has two lateral lobes, the upper are small, and above this 

 a prominent horn directed straight forwards and never absent in adult specimens of 

 E. antarctica, making it quite characteristi(; of the species. 



In the ventral aspect the appearance is quite different from that of similis. The 

 o-enital opening is oval, almost round, with lateral cushions, and above the upper edge 

 of the genital opening guarded by a chitin ridge, is the horn. 



The whole swelling is quite symmetrical, rather conical, and occupies (|uite the 

 lower part of the segment. 



The first pair of feet have the outer margin very concave above and very convex 

 below, with a bunch of hairs on the Re 1 , and a long seta. The seta of Re 2 is also 

 very long and thin. The Re 3 is only half the length of the coalesced Re 1 and 2. 



In the second pair the Re 1 has a very short Se, that of Re 2 is very long and 

 more than twice as long as the Se 1 of Re 3. 



In Re 3, the Se 1 does not reach the origin of Se 2, the Se 2 does not quite reach 

 the end of the segment, and is three times as long as Se 3 and twice as long as Se 1. 

 The Se 1 and 2 are very greatly curved and almost sickle-shaped. 



