ENTOMOSTRACA OF MINNESOTA. 195 
Daphnia ventricosa Hellich. 
Hellich ’77; Elymann ’87. 
A large pelagic species without the toothed comb of the claw. The 
head is depressed, small, with rather protuberant front and long beak 
inclined caudo-ventrad. The short oval shell is deeper than the head, 
well rounded above and below. Spine long and straight, springing 
from the middle of the caudal margiti. The antennal sete are short 
and thick and have the first segment longer than the second. The 
first abdominal process is twice as long as the second, with which it is 
united. The post-abdomen narrows toward the end and is hairy lat- 
erally. Anal spines14. Claws with sete. Length 2.28 mm. 
Daphnia caudata Sars. 
Fischer ’54 (longispina). 
A large species without basal spines upon the claws. Head some- 
what depressed, about one-third as long as the body, ventral margin 
slightly concave; beak long, inclined caudo-ventrad. Shell oval, 
with no depression between body and head. Spine long, springing 
from the middle of the caudal margin. Eye near margin of head, 
with few crystallines. Antenne with short thick sete whose basa} 
segment is longer than the second. Post-abdomen narrowed toward 
the end. Anal spines 9 to 12. Claw with a row of sete on the con- 
cave, and two spines on the convex aspect. The two cephalic 
abdominal processes united. Length 2.3 to 2.67 mm. 
This species is said to resemble D. longispina. It would appear to 
be closely related to D. ventricosa. 
* Daphina hyalina Leydig. 
PLATES XXII, Fies. 7, 8; X XVII, Fic. 6; XXXV, Fia. 16; XLIX, Fies. 3-5; 
LILI, Fies. 1-4. 
Leydig ’60; Sars ’64 (galeata); Hellich ’74 (gracilis); P. E. Mueller ’68 (pellucida); 
Birge ’78 (levis); Herrick ’&3 
The general form and appearance down to the minute details in 
this species are similar to D. kahlbergensis, with which it is almost 
always associated, except the head which is subject to an astonishing 
range of variation. A comparison of Figs 1 and 5 of Plate LIII, 
which were drawn by camera upon the same slide, illustrates the simi- 
larity. The body is pellucid. Shell, sub-oval, with long, straight, 
toothed spine as long as the body without the head, and inserted high 
up. Post-abdomen narrow with discrete processes, anal teeth about 
ten, terminal claw finely fringed or smooth. Eye small, either near 
13 
