188 
BRACHIONUS PALA, TYPE ForM. SEXUAL CYCLE. 
Winter eggs Summer eggs sn 
1305 Males Maleeggs Tet ee 
Free* oa Free* | Carried viduals 
Och) 20%. a: ey eS 964 96 48 
Nowe, teen cles 765 765 485" | 1.700: 3,060") onays 6,885 
Newt A. TAO). “82980 | 7,245 ==) 63-135 lets aise |agomons 134.550 
Novicl0e cu), | 47680 |=—— | — | 43,680 | 68,880 |114,240'| 189 980 
Now 2a soe. aa 742 |" 2,296)| — | 46,7461) 86.040) IBBe754 ol ee 
Deen sane == | 1,380.) ——— | — | 68,310. |..66; 240) 3/56 03001) oieeeeas 
Deessitsee.e — 424 | —— | — | 16,112 | 17,384 | 22,472 | 36,464 
Decale o pe gece a 17,808 | 1,113 | 18,921 | 14,469 
Ween Joe | —— ———  — | —— 371 742 371 
* Includes free eggs of other varieties also. 
culmination of a pulse is very large. For example, the sudden ver- 
nal pulse of 716,982 on April 24 is accompanied by 28,584 free 
winter eggs. The pulse declines to 22,224 on April 29, and the free 
winter eggs rise to 95,841, and the empty lorice to 26,114. 
Females carry 1-5 summer eggs, and 1-8, or even more, male 
eggs. There is great variation in the size of the summer eggs, these 
and the male eggs appearing almost to intergrade. 
Brachonus pala, including Bb. ampliceros, 1s a common. constitu- 
ent of the plankton of shallow warm waters. It has not been 
reported from the larger and cooler lake waters by Apstein (’96), 
Burckhardt (’00 and ’00a), or Jennings (94, ’96, and ’00). Zacha- 
rias (’98) and Marsson (’00) find it in the summer plankton of 
smaller lakes and ponds in Germany. Seligo (’00) records it from 
April to October, with a maximum in August, in Prussian lakes; and 
Lauterborn (’98a) finds it to be perennial and polycyclic in the 
Rhine. Schorler (’00) reports both pala and amphiceros from the 
Elbe, the former being abundant in May and sporadic during the 
summer, while the latter was abundant in April, June, and Septem- 
ber, and rare at other times during the warmer months. Zimmer 
