BELONGING TO DAPHNIA- AND OTHEE ALLIED GENEEA. 221 



Daphnia longispma^ var. major, Gr. 0. Sars. 

 lacustris, G. 0. Sars. 



,, var. vicina, Ricliard. 

 hyalina, var. pelhicida, Gr. 0. Sars. 

 galeata, G. 0. Sars. 



,, var. oltusifrons^ G. 0. Sars. 

 Hyalodaphnia Jardinii, (Baird). 



,, Kahlhergensis, Schoedler. 



Dactylura puhescens, G. S. B. 



,, magna, (Strauss). 

 Moina rectirostris (0. F. Miiller). 



Genus DAPHNIA, 0. P. MiiUer. 



Daphnia pulex, De Geer, (PI. YIL, figs. 1-8). 



Dapihnia pulex, De Geer, Mem. Pour Servir. a I'Hist. 

 Ins. 442, t. 27, figs. 1-4 (tide Baird). . 

 1850. ,, ,, Baird, Nat. Hist. Brit. Entom., p. 89, 



pi. YL, figs. 1-3, pi. IX., fig. 5. 



1860. ,, ,, Leydig, Naturgeschichte der Daphni- 



den, p. 117, pi. I., figs. 1-7. 



1861. ,, ,, G. 0. Sars, Om de i Omegnen af Chris- 



tiania forekommende Cladocerer, 



p. 15 (separate copy). 



1871. ,. ,, Fric, Die Krustenthiere Bohmens, p. 



231, figs. 33a, b. 



Female. — Seen from the side (fig. 1) the shell is subovate, 

 somewhat narrowed toward the front and less so towards the 

 posterior extremity, the middle of which is produced into a short 

 stout spine : the height is equal to considerably more than half 

 the entire length. The head is rounded off in front, its inferior 

 margin forming a more or less deeply sinuated curve, which 

 terminates in a slenderly produced, sharp beak : its posterior 

 margin bearing the slight protuberance of the antennule with 

 its sensory setae. Dorsal margin only slightly arched in the 

 middle, sloping with a gradual curve to the head, but much 







