STATE GEOLOGIST. 181 



seen through the body of the male, is liable to be mistaken for 

 eggs. 



Psevido-diaptoinus pelagicus. (Sp. n.) 



Esther compact; thorax alike in the sexes, antennse short, 

 seeming 22-jointed; first foot small, both rami 3-jointed; fifth feet 

 in the male with but small rudiments of the inner rami, basal 

 portion heavily armed with short teeth, otherwise almost as ia 

 Diaptomus; fifth feet of female slender, alike; abdomen in male 

 very slender, with short stylets armed witli five terminal setae and 

 a series of bristles on the inner margins, distal margin of segments 

 of abdomen toothed; a series of spines also ornaments the middle 

 of the first segment below; abdomen of female short and very 

 spiny, first joint thick, second slender, oblong, third joint short; 

 length of abdomen supplemented by that of the elongated stylets, 

 which are spinulous on their edges; ova-sac ovoid, eggs numerous; 

 opening of operculum vulvae with lateral projecting lips. 



This species is ornamented with irregular markings of brownish 

 color which give it a strange appearance not observed in any other 

 copepod. The size is like Temora velox, which the female resem- 

 bles a little, a resemblance enhanced by the elongated stylets. By 

 some changes in the definitions of Metrida and Pleuromma these 

 three genera could be united, but there would then be no valid 

 excuse for not admitting Diaptomus^ so that, on the whole, it may 

 be well to let matters stand until we reach some better understand- 

 ing of the natural generic affiuities of these animals. 



Habitat, Mississippi sound, gulf of Mexico. 



Genus Dias, Lilljeborg. 



Slender ; cephalothorax very long, narrow in front ; abdomen 

 with five segments in the male, in the female with three; antennae 

 20-jointed, nodose ; secondary branch of antennules one-jointed, 

 small ; labrum ha-ge; posterior maxillipeds short; swimming feet 

 with 2- and 3 jointed rami; fifth feet with a single ramus. 



Dias long-iremis, Lilljeborg ? 



Unfortunately the gathering v/as insufficient to determine with 

 ciirtainty the identity of our species with the above, but the female 

 agrees quite well; and those points in the young males seen 



