ENTOMOSTRACA OF MINNESOTA. 191 
bles and the front of the head, and about midway between the tip of 
the beak and the dorsal surface of the head. Pigment speck very 
small, less than half the diameter of a lense of the eye, and placed 
midway between the eye and the posterior margin of the head. The 
latter concave, the beak extended backward and applied against the 
margin of the shell. Swimming antenne reaching the middle of the 
shell, their hairs moderately robust, the first segment not longer than 
the second. No emargination separating head from body, but the 
dorsal surface very slightly sinuate there. Abdominal processes all 
distinct, anterior much the longest. Caudal claw with accessory 
teeth, about six in number, the three proximal the largest. Anal 
spines about ten. Posterior spine of the shell given off from the 
middle of the valves, in the adult female a third to a half as long as 
the valve. Shell moderately coarsely marked in quadrangular areas, 
the lower and dorsal margins spinulose from the middle backwards. 
Length 2.0 mm., depth 1.0 mm. Heart Lake, Yellowstone Park.”’ 
Daphnia gibbosa Hellich. 
Hellich ’74 and ’77; Elymann ’87. 
Body large, very high. Head depressed, ventral margin strongly 
concave. Eye large, with few crystallines. Antenne long, scaly. An 
obvious depression separates head and body. Spine short, above the 
middle. Abdominal processes united. Anal teeth 17 to 19, dimin- 
ishing dorsad. Claws with a comb of teeth. Color reddish. Length 
2.01 mm. 
Daphnia ovata Sars. 
‘*Caput a latere visum ante oculum fere angulatum, margine inferiore leviter con 
¢avo in rostrum longum apicem versus attenuatum, extremitate tenuissima exeunte- 
spura visum ut in D. pennata cordiforme. Testa cetera a latere visa ovata, margine 
superiore et inferiore in femina adulta fere eequies arcuatis, postice in medio spinam 
formans brevissimam vel omnino obsoletam. Processus anteriores duo abdominis dis- 
juncti. Margo posterior postabdominis in medio sinuatus, utrinque aculeis 20-22 
armatus. Color albido—flavescens vel-virescens. Longit. circit 3 mm.’’ 
No one besides Sars seems to have seen this species. We suspect 
it is simply D. schefferi. 
Daphnia obtusa Kurz. 
Lilljeborg 753 (pulex); Kurz ’74; Hellich ’77; Elymann ’87; Daday ’88. 
Head short, front rounded, ventral margin slightly sinuate, beak 
short, acute turned caudad, Eye remote from the margin of head. 
Crest absent. Body oval, margins convex, spine nearly absent. Post- 
