some Entomostraca. 19 



Euch<jeta Atlantica, n. sp. 



Cephalotliorax pubescens, 4-articulatus, capite non lateraliter 

 angulatus, postice obtusus. Antennae anticee fere corporis 

 longitudine, setas Enchcetce diademae fere similes, setd pos- 

 ticd penultima dimidium posticae apicalis non superante, setis 

 antepenultimis perbrevibus. Pedes natatorii quinti paris 

 foeminae nulli, quarti grandes. Abdomen foeminae 3-articu- 

 tmn, articulo primo foeminae secundum longitudine non supe- 

 rante. Seta caudalis longa, foeminae nuda. Abdomen maris 

 4-articulatum ; segmento primo brevi. 



The second pair,,of antennae and first four pairs of legs of this 

 species could hardly be distinguished from those of Undina plu- 

 mosa. 



It may be doubted whether the male and female here described 

 belong to the same species, but they were several times collected 

 together without any other nearly allied species, were caught in 

 rather large numbers, and agreed in those organs which do not 

 present sexual differences. 



The anterior antennae of the female are "093 in length ; the 

 setae are very short, but arranged as usual ; some few are very 

 long, and one or two are plumose. Two of the apical hairs are 

 very long, also the posterior penultimate, and the anterior hair of 

 the fourth segment, counting from the apex. The posterior ante- 

 penultimate seta is very small. The anterior antennae of the male 

 are different in appearance, owing to the absence of long setae ; 

 the small ones are very easily broken off, so that I never found a 

 specimen with them all attached. There are three long hairs at 

 the apex, one of them as long as the four apical segments. 



The second pr. antennce are formed as in Calanus. The long 

 apical hairs of the organ are eleven in number. The accessory 

 branch is longer than the organ, the four intermediate joints are 

 short and indistinct, and the apical hairs are three in number. 



The second pair of maxillipeds are *021 inch in length, and divided 

 into four segments. They resemble those of Calanus, but are 

 longer in proportion, and consist of four segments instead of three, 

 as usual in that genus. The hairs are large, and seated on pro- 

 tuberances. 



The third pr. maxillipeds are -05 in length, large, pediform, and 

 consisting of seven segments ; the basal segment is large, with 

 several spinose hairs, the second is almost twice as long as the 

 first, and forms almost a right angle with it. The five apical seg- 

 ments are small and indistinctly separated ; they each bear two or 



c 2 



