no. 1651. REPORT OV THE OSTRACODA—SHARPE. 405 



An attempt was made to breed them true, with a view to ascer 

 taining if they would cross, but all specimens invariably died within 

 a week or so when placed in any of the ordinary aquaria. Their 

 life period is evidently very short and transitory, which may account 

 in part for lack of success. Of course, a short life history might be 

 expected from the transitory nature of their habitat. 



They were found associated with Cypria obesa, Spirocypris tuber- 

 culata, Cypridopsis vidua, Cypria dentifera, Cyclocypris Icevis, 

 ('(iixlonii /■< <-tic<iiul((, and Cyprois marginata. These, of course, were 

 not certainly present in any one locality. For instance, Cyprois 

 marginuta was found in only one small temporary grassy pool in 

 Jackson Park, which very soon dried up, while most of the remain- 

 ing forms occurred quite generally in all the swamp and dune ponds 

 of the region southeast of Chicago and of northwestern Indiana. 

 For the character of the plant life of the waters of this region see 

 under Notodromas monacha. 



Distribution world-wide; all Europe; Guanajuato, Mexico, in a 

 collection sent to the .U. S. National Museum by Dr. A. Duges, French 

 consular agent. Accession No. 15606. A few specimens were here 

 found associated with Cypris pellucida. 



8. CYPRIS INCONGRUENS (Ramdohr). 



Plate LIV, figs. 1 3. 



Cypris incongruens Ramdohr, Ma^. der Gesell. Naturforsch. Freunde, 

 Berlin, II, 1808, p. 86. 



('Hl>ris aurantia Baird, Nat. Hist. Brit. Entomos., London, 1S50, p. L59, 

 pi. xix, fig. 13.— Fischer, Abh. der Mathem. I'hys. Klasse der kgl. Bay- 

 erischen Akad. der Wiss., VII, 1855, p. 650, pi. i, fips. 29-31, 60, 61. 



Cypris incongruens Brady, Trans. Linn. Soc. London, 1S0S, XXVI, p. 362, 

 lil. xxiii, figs. 16-22. — Brady and Norman, Trans. Royal Dublin Soc. 

 L889, IV, 2d ser., p. 73, pi. xn. figs. 8-9.— Vavra, Arch. Naturw. Durcn- 

 forsch. Bobmen, VIII, Heft 3, 1891, p. 95.— Croneberg, Bull. Soc. Imp. 

 Natur. Moscou, VIII, 1894, p. 304, fig. 21. — Kauffman, Revue Suisse do 

 Zool., VIII. Fasc. 3, 1000, p. 204. pi. xv, figs. 10-12; pi. xvm, fii,'. 5.— 

 Muller, Zoologica, XII, Heft 30, 1900, p. 77; pi. xm, figs. L2-22. 



Cyprinotus incongruens Sharpe, Bull. Illinois State Lab. Nat. Hist., IV. 

 1S'.)7, p. 187.— SARS, Ann. .MusiV Zool. de 1'Acad. Imp. des Sci. do St. 

 Pgtersbourg, VIII, 1003, p. 222 [28]. 



Dimensions. — Length, 1.5S to 1.75 mm.; height, 1 to .1.01 mm.; 

 breadth, 0.85 to 0.00 mm. 



Soon from above (fig. 2), the shell is widest at its posterior one- 

 third, about one-half as wide as long, rounded posteriorly and 

 anteriorly, the left shell overlapping the right. Seen from the side 

 (fig. 1), the right shell is highest just back of the middle, the height 

 here being about three-fifths as great as the length and sloping 

 rapidly anteriorly from just back of the eye-spot; the anterior and 

 lower posterior margins of the right valve armed with a row of 

 prominent tubercles (fig. 1). 



