236 GEOL. AND NAT. HIST, SURVEY OF MINNESOTA. 



toward the end, rounded in front; the terminal claws are small and 

 have two basal teeth. The dorsal margin of the post-abdomen is cov- 

 ered with tufts of hairs. The winter eggs have no ephippium. Length 

 0.55 mm. to 0.7 mm. The male is smaller and has a lower dorsal keel; 

 the post-abdomen is excavated behind. 



The only differences between the Minnesota specimens and the typi- 

 cal European form seemed to be the absence of the very minute spines 

 on the front of the terminal claws. The eye and pigment fleck are of 

 about the proportions figured by Kurz. Birge's figure of the post- 

 abdomen does not agree with his description fully. Our Minnesota 

 specimens have an obvious but not high keel. 



* Graptoleberis reticulata Baird. 



AJona reticulata — Baird, P. E. Mueller. 

 Lynceus reiiculalus — Lilljeborg, Leydig. 

 Alona esucirostris — Schoedler. 



Shell almost rectangular, reticulate, ventral margin straight, ciliate 

 anteriorly, with two teeth behind. Pigment fleck smaller than the 

 eye. Post-abdomen short, narrowed towards the end, dorsally cov- 

 ered with clusters of spines; caudal claws witli a minute tooth at the 

 base. Length 0.4 mm. to 0.5 mm. 



The pigment fleck is nearer the end of the beak than the eye, and 

 is smaller than in the previous species, but, on the whole, there is, 

 perhaps, too great similarity. 



Professor Birge writes that he unites the two species. 



GENUS DUNHEVEDIA King. 



Crepidocefcus — Birge. 



The characters of this group place it rather \xQ,?i>r Alondla or between 

 that and Fleuroxus. Form sub- quad rate with rounded angles; dorsal 

 line uniformly arched, terminating in a sharp angle behind; lower 

 margin convex, armed behind with a single spine as in Pleuroxus 

 unidens, and along the entire length with loose sette. Beak of moder- 

 ate length, acute. Post-abdomen deeply incised in the anal region; 

 lower posterior margin straight, rounded at the apex; ventral margin 

 straight or concave; claws with a single basal spine and a few teeth. 

 The post abdomen is shoe shaped and armed with transverse rows of 

 setfB. 



The antenujB are large, having eight setse and the usual spines. 

 Shell smooth or reticulate. Founded by King to include two species 

 from Australia, D. crassa and 7). sodagra. 



