416 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. xxxv. 



the two terminal being coarser, and somewhat claw-like, faintly 

 toothed, the other two rather plumose. Terminal seta three-fifths as 

 long as anterior edge of furca ; dorsal seta longer, four-fifths as long 

 as furca, and sharply bent near the tip, the two terminal claw-like 

 seta 1 about the same length, and as long as the anterior edge of the 

 furca. The dorsal seta here is unusually long, more strikingly so 

 than amongst any Ostracods with which I am familiar. 



A\ marks. — I know of but one other species of Cyprois having been 

 described — C. madaraszi Orley. This species is about twice the size 

 of ('. marginata, it being about 3 mm. in length, while C. marginata 

 is only about 1.50 mm. long. It is evidently closely related to Noto- 

 dromas in habits, and, in part, structurally, noticeably the six spines 

 on the first maxillary process. Both genera are sexual, the different 

 sexes showing slight differences of furca and form of shell. 



Observations. — This form was kept for several weeks in aquaria. 

 It was quite active, restless, and swam freely through the water, 

 numbers of them coming to the surface of the water, where it lias a 

 unique habit of swimming along in an erratic way just below the 

 surface film, acting as though trying to support itself there; in fact 

 it may often be seen resting quiescent just below the surface film, at 

 some distance from the edge of the aquarium. Many were also no- 

 ticed creeping among debris at the bottom of the aquarium. Many 

 were noted copulating. 



Occurrence. — Large numbers frequented a shallow grassy pool just 

 south of the old Columbian Exposition grounds in Jackson Park, 

 Chicago. This pond was a temporary one, lasting from early spring 

 to early June, when it became perfectly dry.. This agrees with all 

 hitherto recorded reports on habitat. It has hitherto been reported 

 only from Europe, in England (Brady and Norman, 1896), Norway 

 (Sars, 1891), Switzerland (Kaufmann, 1900), Germany (Muller, 

 19.00), and Russia. 



Collected May 3, 1900, Jackson Park, Chicago. 



14. NOTODROMAS Lilljeborg, 1853. 



Monoculus Jurine, Histoire des Monocles^ etc., 1820. 



Cyprois Zenker, Monog. der Ostracoden, 1854, p. 80. 



Notodromas Lilljeborg, De Crust, ex Ord. Mil mis, 1853, p. 54. — Brady and 

 Norman, Trans. Royal Dublin Soc, 1889, p. 95. — Kaufmann, Revue 

 Suisse de Zool., VIII. 1900, p. 251.— Muller, Zoologica, 1900, p. 16.- 

 Sharpe, Proc. U. S. Nat. Mus., XXVI, 1903, p. 974. 



Shell high, smooth. Natatory setae reach to tips of terminal 

 claws. Second antenna' six-segmented in both sexes. First maxil- 

 lary process with six toothed spines. Second foot five-segmented, 

 terminating in three setae, of which two are backwardly directed. 

 Furca with two terminal claws seta-like, and terminal missing, so that 

 furca seems to end in three setae. Two eyes, separate. Sexual. 



