24 Mr. Lubbock on 



W. L. The species was rather common, but tlierc are no females 

 which I can with certainty refer to it. 

 PI. VI. figs. 1 to 5. 



Undina plumosa, n. sp. 



Maris. — Frons obtusa. Cephalothorax postice rotundatas, 4-ar- 

 ticulatus. Antennae anticae cephalothorace longiores, corpore 

 breviores, aliquando dissimiles, setis brevibus, postica penul- 

 timdantepenultima subaequis. Abdomen 4-articulatura. Styli 

 caudales breves ; setis 4, seta secunda longiore, sed non 

 duplo longiore. 



I could not find the usual furcate rostrum in this species. 



The second pair of antennae and first four pairs of legs could 

 hardly be distinguished from those of Enchcsta Atlantica. 



The outline of this species much resembles Undina vulgaris. 



The anterior antennae are '09 in length ; the setae are very 

 short, the largest being situated on the third basal segment ; the 

 anterior and posterior seta of the apical segment are longer than 

 the segment, but all the others are very short. 



The accessory branch of the second pair of antennae is larger 

 than the organ itself, and bears three long hairs at the apex. The 

 four intermediate segments are small, and each provided with one 

 long hair. The organ itself is terminated by two tufts of long 

 hairs, six in the one and five in the other, besides a few short 

 ones. 



The third pair of maxillipeds are '032 inch in length, and are 

 seven-jointed, but the five apical segments are very small. The 

 apical segment bears three hairs, the next I believe two, the third 

 one, the fourth and fifth respectively three and four, the sixth three, 

 and the basal one, I believe, two at the apex, and one at the base. 



First pair of legs '009 in length ; the usual plumose hair at 

 base is, I believe, absent ; there are, however, on both the basal 

 segments several small hairs. The external ramus is three-jointed. 

 The middle segment bears one long hair, and a fringe of small 

 ones ; the apical segment has four long hairs, and a spine at the 

 apex. The inner ramus consists of one segment only, which has 

 five long hairs. All the large hairs on these organs are plumose. 



The fourth pair are larger, 'OIT in length ; the rami are both 

 three-jointed. The smaller as long as tlie first two segments of 

 the larger ramus, which has a spine at the apex of each segment, 

 and two intermediate, as usual, to the apical segment. The usual 

 plumose basal hair is present, but there is no fringe as in the first 

 pair of legs, which may, however, have been broken off". Each 



