THE WATER FLEAS (CLADOCERA) 



693 



18(3) Enclosed in gelatinous mantle. Antcnn; 

 with 3 terminal setae. . . 



simple in fi-malc, cylimlrical, 

 lamily HoU)1'kuu>ak Sars. 



fvl 



Animal enclosed in a large, globular, transparent, (k-licatc hut U>uk\\. Kfblinou> lav oum 

 ventrally and forming 2 valves. Body much compressed, shell of lu-ati and lx..i\ s. , , i' I,, 

 high, as seen from side, leaving uncovered the mouth parts, the ends of the I. • 

 part of body. Antennule small, fixed; with 5-0 olfactory seta.- and lateral s- 

 flagellum. Antennae in 9 long; basal joint curved, annulated; the single tatuvi.', j i.,,., 

 antennae of $ biramous. Post-abdomen large, 

 fleshy, not bent forward; with rather long, 

 curved anal spines and clusters of very fine 

 spinules; abdominal setae long, set on single, 

 long, conical projection. Claws large, curved, 

 denticulate, not set ofT from body by distinct 

 joint. Eye small, with numerous len.ses; ocellus 

 small. Intestine simple with 2 hepatic ceca. 

 Branchial sac on second to fifth feet. Color 

 transparent. Swims on its back. 



Sole genus with characters of family. 

 Holopedimn Z3.dd3.ch. iSss ■ 19 



19 (20) Ventral margins of valves 

 with fine spines. 

 Holopedium gibberum Zaddach 1855. 



Post-abdomen elongated (ca. one-third 

 length of body) and tapering; anal spines 

 numerous, up to 20. Claws with i 

 basal spine. Length, 9. 1-5-2.2 mm.; 

 $ , 0.5-0.6 mm. 



This remarkable and beautiful species 

 is not uncommon in open water in 

 northern lakes; has been found in the 

 Great Lakes, and in many inland waters, 

 both lakes and smaller bodies of water. 



Figs. 1060, 1061, a. Holopedium gibberum 

 (gelatinous case not shown). (See also 

 Fig. 1061.) 



0.5 MM 



20 (19) Ventral margin of valves smooth. 



Holopedium anuizoniium Stinpi-Im looj- 



Post-ahdomcQ sh«>rt. I)lunt («.a 

 one-fourth of IkkIv in It-nKthl, i»ilh 

 7-S anal spines, the row continued 

 forward by .% 4 verv •-'" ■ 

 Claws without has.1I 

 inal setae ver>' loni; a 

 unknown. Ix-ngth. V ' >- 

 Charles, L»»uiMana. 



Fio. ic/ii. a UMptJimm 

 b IlolofuJium aHMiomU 



>ulr*. 



i 

 i-ike 



