

CYCLOPOIDEA. 



1119 



gerce, valde flexiles, setis scepe longiusculis, quaquaversum insistentibus, 

 antennd dextrd maris non (?) geniculatd. Pedes postici obsolescentes, 

 uni-articidati, duabus setis valde incequis et divaricatis instructi. Setce 

 caudales mediocres. 



Like the Ibntellw in the beak, eyes, cephalothorax, maxillipeds, ante- 

 rior feet, and posterior antennae. Anterior antennas irregularly 

 setigerous and very flexible; setae often rather long, and turned 

 different ways ; the right of the male antennae of first pair not (?) 

 geniculate. Posterior feet obsolescent, one-jointed, furnished with 

 two very unequal setae, which are much divaricate. Caudal setae 

 moderately long. 



The longish setae of the antennae and especially their pointing in 

 different ways, instead of being arranged along the anterior margin, 

 give these species quite a different aspect from the Pontellae. Moreover, 

 the longer seta of the rudimentary posterior legs is seen in a vertical 

 view projecting from the extremity of the thorax, either side of the 

 abdomen. The male right antenna is probably without a genicula- 

 tion, this character being compensated for by these organs being quite 

 flexible throughout. Yet, I am not altogether confident that any of 

 the specimens examined were males. The inferior and superior eyes 

 are the same as in the Pontellae. The cephalic segment is often dis- 

 tinct. The species observed were found with the Pontellae and Calani 

 in the open seas of the torrid and temperate zones. 



The name Acartia is from the Greek «x^t 0$ , unshorn, and alludes 

 to the irregular arrangement of the setae of the anterior antennae. 



Acartia, Dana, Amer. Jour. Sci., [2], i., 227, and Proc. Amer. Acad. Sci., ii. 25, 

 where the following new species are briefly described by the author. 



Acartia limpida. 



Gracilis. Frons triangulatus. Ceplialothorax posticd obtusus, 5-articu- 

 latus, capite discreto. Antennas antico3 lath divaricatm, rectiusculae, 

 vix corporis longitudine, 7—$-articulato3, articulis ultimis tribus brevi- 

 bus, precedentibus longis; setis prwlongis, penultimd posticd dimidio 

 breviore quam apicales. Styli caudales oblongi, tenues, setis divari- 

 catis. 



