THE WATER ELEAS (CL ADOCKRa) 



703 



64 (63) Vertex angulated, with spines. Antennulcs long. 



Ccriodaplinia rotunda Sars 1867. 



General form much like prccedinR. Head anslcl at vcrtr. 

 with spmes Antennulcs lon^ and slender. I'ost al-i.- • ^ 

 samewhat enlarged, hut not s(j much as in latuaudata t 

 toward apex, ohiKiuely truncate, with 7 o slender an.i 

 Color yellowish or brown, not transfiarent. IxrnKth ', • , 

 i.o mm.; $ , to 0.6 mm. • ♦ • 



Rare, Wisconsin. Both this species and the precetJinx live 

 among weeds. 



Fig. 1088. Ceriodaphnia mlutula. (After Lilljcburjt ) 



65 (49) Head large and usually extended. Antennulcs larRc and fri-idy 



movable. Post-abdomen with posl-anal extension. . 66 



66 (67) Body compressed. Valves elliptical, crested dor.siiilv. C()mi)l»;ii-ly 



covering body. Ocellus present. Fornix and atxlominal 

 process well developed. . . . Mohwdaplmia Herrick 18S7. 

 Cervical sinus present; no cervical gland. Valves tumid in posfero-dorsiil rrpion; crcsJed: 

 minute spines on ventral margin; sharp angle, not spine, at junction of durvil an.| venirai 

 margins; marked with oblique striae, usually invisible in preserved siH.-cimcn^ .\ntennulc» 

 attached on ventral surface of head, sense-hair about middle: olfactory set.ic small. One larjje 

 abdominal process, broad, concave in front, somewhat saddle-shajXHl, forming a transition to 

 the condition in Moina. Post-abdomen as in Moiua, with slender j)ost-anal projection l>earinx 

 about 10 finely ciliate spines and a much longer distal spine with 2 unequal pronKs. the biJrmi 

 (Fig. 1094). Claws denticulate. Summer eggs numerous. Male (.South .\merica) much like 

 Moina, with large curved antennules. 



Only one certain species. . Moinodaphnia madcdyii (King) 1853. 



Color yellowish, transparmt. 

 Length. 9. ^^- 'o ^^■ 



Louisiana. In weedy pcx>l« 

 and lakes. 



Ilerrick's M. alabamrnsis is re 

 ported as larger (1.68 mm ) ami 

 may possibly be a different *pe 

 cies. Herrick had only Kinx's 

 very imperfect tles^ription for 

 comparist)n with hi-; form, .ind 

 his own description ' . 1- 



ingly imiK-rfect. " >( 



M . mdiUayii from I v 1 



form identical wiiii ihai irom 



0.1 MM. • ■ >- ' ' ' " -^ ^^"^ ^^'•^^"^ 



Fig. io8g. .\foimhiaphmj madtiyii. 



67 (66) Body thick and heavy. Valves somewhat rhomlH)idal. not wholly 

 covering body. Fornix small. Ocellus absent. AMominal 

 process represented by horse-shoe shaped told. 



Moina Haird 1S50 . . 68 



Cervical sinus present. Valves thin, obscurely reticulated or striate<l; no ix.sterior Vi^nt. 

 Head large, thick, rounded in front; sometimes with (lee|) depres.sion alH)ve eye; no r. .strum. 

 Antennules long, spindle-shaped, freely movable; lateral sense-hair al)«)ut muldle .No regular 

 abdominal projection, but in old 9 a horse-shoe shaFx-d ridge which closes the briHMl-<aviiy. 

 Post-abdomen extended into conical post-anal part, bearing cihatol si.ines ami Indent i uw» 

 small; abdominal setae very long. Summer eggs numerous; ephippium oval, with i or 3 c«*. 

 Antennule of $ very long and stout, modified into clasping organ; denticulate, witti Miiaii 

 recurved hooks at apex. First foot with hook. .... , -n, ^ ^ t, 



The species of Moina ordinarily inhabit muddy pools and similar placw. ITiey arc sclt- 

 bodied, weak creatures; liable to be much distorte.l by preserving llui.ls. I he spcoc* arc mucn 

 alike and often hard to distinguish unless $ and ephippial 9 arc present. 



