some JEntomostraca. 31 



Clytemnestra Atlantica, n. sp. 



Corpus pyriforme. Cephalothorax acute rostratus 5-articula- 

 tus, segmentis postice rotundatis, non dilatatis, marginibus 

 posterioribus fere rectis, segmento postico tamen denticulato. 

 Antennae anticas breves. Abdomen promiscue 4-articulatum, 

 Styli caudales mediocres, setis quatuor. 



This species may at once be recognised by the form of the body, 

 which is almost pyriform, the posterior angles of the cephalatho- 

 racic segments not projecting laterally. The anterior antennae 

 are very short, scarcely as long as half the breadth of the cepha- 

 lothorax. The posterior angles of the cephalothorax are acute. 

 The abdomen is short, and the segments are not distinctly marked. 

 It may be divided into two parts, one broad, and consisting, 

 perhaps, of three segments, the last of which bears on each side 

 a small appendage, terminated by two hairs ; the other part narrow, 

 short and bearing the two slender stylets. 



It was collected in the Atlantic, and, as there was only one spe- 

 cimen, I did not dissect it, but I think there can be little doubt that 

 it belongs to the genus Clytemnestra of Dana. 



Length -09. 



PI. XII. figs. 12, 13. 



Corycceus Sutherlandn. 



Cephalothorax mediocris, segmento quarto elongate acuto. Con- 

 sjncilla fere contigua. Antennae anticae 7-articulatae, setis 

 longissimis, nudis. Antennarum posticarum digitus articulo 

 secundo brevior ; seta articuli primi nuda. Abdomen 3?-ar- 

 ticulatum '02 unc. long. ; styli caudales abdomine vix breviores 

 •019 unc. long. ; seta caudalis maxima '013 unc. long. 



Anterior antennce '012 inch in length. The hairs are nearly twice 

 as long as the organ itself. 



Posterior antennce '0\5. Four-jointed. The basal segment bears 

 two setae, one short, the other extending beyond the apex of the 

 organ, and appears to be in some measure opposable to the fingers. 

 The second segment bears two teeth at the inner apex, and two 

 " fingers," of which the larger is two-jointed, and the basal part 

 is provided with two teeth. The larger finger is shorter than the 

 second segment, but very little so. The large spine is not 

 plumose. 



The third pair of natatory legs consist of a two-jointed basal part, 

 and two three-jointed rami. The inner ramus is short, being 

 shorter than the two first segments of the other. The outer 



