126 Mr. J. Lubbock on some Arctic species of Calanidae. 



The second pair of antennae consists as usual of a basal part 

 and two rami, which are nearly of equal size. The largest is 

 2-jointed. The basal segment bears two long hairs on one side 

 and a little tuft of shorter ones on the other. This little tuft is 

 present also in all the Calani I have been able to examine, in 

 Diaptomus Castor, and in a South American Diaptomus not as yet 

 described. The apical segment bears about 12 long hairs. The 

 second branch consists of about 7 segments, only partially di- 

 vided from one another, of which the first and the last are the 

 largest. There are 3 long hairs at the apex and about 9 along 

 the margin. 



The second pair of maxilla are a somewhat triangular plate, 

 which shows traces of being divided into 3 segments, and bears 

 about 20 setose hairs. 



The third pair of maxilla, or first pair of feet according to 

 Dana, are cylindrical, and consist of 7 segments gradually de- 

 creasing in size. 



All these organs are attached to the first cephalothoracic seg- 

 ment, the other 5 each bear a pair of natatory legs. 



The natatory legs consist each of a 2-jointed basal part and 



2 rami. In this species the rami of the first pair each have 



3 joints, and the outer one is rather longer than the inner 

 (PI. V. fig. 6). 



The rami of the fifth pair are reduced to 2 segments, and the 

 basal part is armed on its inner margin with a row of short stout 

 teeth (fig. 1). 



The abdomen has 4 segments, of which the anterior is the 

 largest, and the second next. The lamella? are not much longer 

 than the last segment. 



Colour ? 



C. plumosus, n. s. Frons rotundatus. Cephalothorax magnus, 

 6-articulatus, postice rotundatus, in medio acutus. Antennae 

 anticae corpore paulo longiores, setis longis. Abdomen 4-arti- 

 culatum, stylis brevibus. Pedes biremes primi, ramis 4-, 

 quiuti ramis 3-articulatis. 



Long. t 3 q unc. 



Hab. Mare Arct. N. Lat. 77°, W. Long. 71° 37'. 



This species much resembles the preceding. The second 

 maxillae, mandibles, and maxillipeds are similar. The second pair 

 of antennae differ in having another small segment at the apex 

 of the larger ramus. The hair at the apex of the penultimate 

 segment is about the same size as the rest, while in C. magnus it 

 is much longer than the corresponding hair of the preceding 

 segments. 



The first pair of natatory legs (fig. 4) have 4 segments to 



