90 TWELFTH ANNUAL BEPORT. 



Sp. 1. Graptoleberis testudinaiia, Fischer. 



Lynceus testudinarius, leydig, lilljebobg. 

 Lynceus reticulatus, frig. 

 Alona teatudinaria, schoedijER. 

 ChraptolMberis testudinaria, kurz. 

 Oraptoleheris inermis, bibge. 



Form trapezoidal; lower margin straight, armed behind with two^ 

 teeth, thickly beset with long hairs in front; the dorsal margin is 

 not greatly elevated, rounded at the posterior angle, forming a 

 slight '*hump" where it unites with the head shield. The head and 

 shell are reticulated with hexagonal or quadrangular markings. 

 The shell gapes below and rises to a sharp ridge above. The an- 

 tennae have long rami, the antennules being hardly longer than 

 the fornices. The eye is large; the pigment fleck is small. The 

 post-abdomen is narrowed toward the end, rounded in front; the 

 terminal claws are small and have two basal teeth. The dorsal 

 margin of the post-abdomen is covered 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 

 typical 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 a2:ree with his description fully. Our 

 Minnesota specimens have an obvious but not high keel. 



Sp. 2. Graptoleberis reticulata, Baird. 



Alona reticulata, baird, p. e. mueixer. 

 Lynceus reticulatus, lilljeborg, letdig. 

 Alona esocirostris, schoedleb. 

 Oraptolel)eris reticulata, sars, kurz. 



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 covered with clusters of spines; caudal claws with 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. 



