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164 GEOL. AND NAT. HIST. SURVEY OF MINNESOTA. 
more than half as long as the height of the head), hairy, straight, 
spindle-shaped, inserted somewhat behind the middle of the lower 
margin of the head and not in a special depression, flagellum one- 
third from base 0.21 mm. long. Body subject to great variation, but 
always much wider than the head. Lower shell margins sparsely 
spined to near the posterior angle. Abdomen slender, with several 
teeth in front of the claws. Claws slightly curved with a basal ex- 
ternal series of strong teeth and a continuous inner series of fine 
spines. Lateral abdominal spines twelve or thirteen. Posterior 
margin above the anus slightly hairy. Ephippium with one egg, 
ephippial female with an abdominal process. Shell with elongate 
hexagonal markings. 
VARIETY B—Proportions exhibited by the following measurements: 
Length, 1.1 mm.; length of head 0.41 mm., height of head 0.46mm. 
The head is strongly depressed, excavated above the eye. Antennules 
slender, long, hairy, attached far from the eye at a sharp angle of the 
inferior margin, flagellum nearer the middle than the preceding. 
Antenne very hairy. Body less robust than the preceding, ventral 
margin sparsely hairy to a point some distance from the posterior 
angle, thence to the upper posterior angle armed with minute closely 
set spinules or teeth. Abdomen slender, without the numerous small 
teeth above the claws on the front margin, claws with about ten strong 
basal teeth and a continuous inner series. Lateral abdominal spines 
ten or twelve. In neither variety have we seen any other markings 
than the point-like elevations scattered over the shell except upon the 
ephippium. Almost the only reliable difference between these varie- 
ties seems to be in the form and insertion of the antennules and the 
outline of the head. 
* Moina paradoxa Weismann. 
PLATES XXXIX, Fia. 9; XL; XULI, Fies: 1; 3, 4, 6,°7, 9. 
Weismann ’77; Gruber and Weismann ’80; Schoedler ’77; Hellich ’77 (fischeri); 
Herrick ’84; Moniez ’88 (azorica). 
This species may be distinguished from the preceding by the fact 
that the head is short and not excavated above the eye, the teeth of 
the terminal claws are reduced to bristles in two series, the first foot 
of the male has a long flagellum, longer than the whole member, the 
male antennule is very long and flexed at about the middle, and the 
ephippium contains two winter eggs. 
The mature summer female is almost monstrously deformed by the 
multitude of young in the brood sac, which swell that cavity into a 
great sub-spherical sac extending in all directions beyond the ordi- 
