162 GEOL. AND NAT. HIST. SURVEY OF MINNESOTA. 



produced, which is one of the best distinctions of the species, as this 

 is, perhaps, the only case (Weismann '76-' 79). The first generation, 

 springing from the winter eggs (impregnated eggs), is composed solely 

 of females which reproduce parthenogenetically; the second brood 

 contains sexual males and females, thus completing the cyclus. 



To the above, which is reproduced with a few verbal changes from 

 the first edition, it may be added that the interesting genus Moina- 

 da2)hnia, found in Alabama, makes the transition toward the genus 

 DapJmia and its immediate allies complete. It should not be over- 

 looked that there are several forms oi Moina which have the anasto- 

 mosing stride upon the shell which is characteristic of Simocephalus, 

 while the ephippium has the characteristic hexagonal marking of 

 Ceriodaphnia. The synonomy of the genus is uncertain, and there is 

 no doubt that several authors have confused more than one species 

 under a single name. 



The following artificial key may assist in placing the species, but 

 should not be too mechanically relied upon. 



KEY TO THE GENUS MOINA. 



I. Shell not sculptured or simply dotted. 



A. Spines of the abdomen fewer than nine. . . micnira [not described.] 

 * B. Spines of the abdomen nine or more. 



a. Claw with a basal series of strong spines externally. 



* Ephippium with two eggs, shell reticulate. . . 'braeliiata, 162 

 ** Ephippium with one egg, shell smooth. . . rectirostris, 163 

 h. Claw with a basal series of fine hairs externally and a 

 continuous series of the like internally. 



fisclieri, 165; paradoxa, 164 

 II. Shell more or less covered by anastomosing striae. 



A. Claws smooth propiiiqua, 165 



B. Claws with teeth lilljeborg'i [not described in the text.] 



[i^ot noticed in the key: azorica, 165; salina, 166; banflfyi, 166] 



Moina brachiata Jurine. 



Plates XXXIX, Figs. 5-8; XLIII, Figs. 1, 2. 



Jurine '20 (Monoculus brachiatus); Straus-Durckheim '19-'20 (Daphnia macrocopns); 

 Zaddach '44 (Daphnia brachiata); Lievin '48 (Daphina brachiata); Baird '50; 

 Leydig '60 (Daphnia brachiata); P. E. Mueller '68; Uljanin '75^; Kurz, 74; Hel- 

 lich '77; Schoedler '77; Birge '78 and '91; Herrick '82 and '84; Richard '88^; 

 Lund '70-'71. 



It is quite certain that the above bibliography includes several in- 

 stances where the name M. brachiata is applied to other species or to 

 include several species, but it seems best to place all in evidence. 



