W4: 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. 



A^arietyB — 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. 

 AnteunjB 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, Fig. 9; XL; XLI, Figs. 1, 3, 4, 6, 7, 9. 



Weismann '77; Gruber and Weismann '80; Schoedler '77; Hellicb '77 (fischeri); 

 Herri ck '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- 



