Notes on Cladocera. 107 



Glacialis. Cambridge, Mass., 1876.; rare. Male not seen. The 

 specific name is taken from the pond in which it was chiefly 

 found. 



SPECIES 4. 



Alona Spinifera. Schodler. 



Alona spikifera. Schodler (Neue Beitrage, p. 18, PL I; fig. 17-22). 



Specimens belonging to this species were scantily found in 

 Madison, Wis., and were quite common in Southampton, Mass. 



SPECIES 5. 



Alona Oblonga. p. E. Miiller. 



Alona oblokga. p. E. Milller, 1. c, p. 175, PI. Ill, fig. 22-33. 



Length, 0.9 mm. 



One specimen, closely agreeing with Miiller's description, was 

 found in Merrill's Springs, near Lake Mendota, Madison, Wis., 

 Sept., 1877. 



On the front side of the second joint of the outer antennary 

 branch was a cluster of spines. In this it differed from Miiller's 

 description. 



SPECIES 6. 



Alona Tuberculata. Kurz. 



Alona tubekculata. Kurz, 1. c, p. 51, Tab. II, fig. 3. 



The chief difference between my specimens and Kurz's, seems 

 to be that mine have a greater number of rounded elevations 

 than his. 



The shape of the post-abdomen does not appear to be identical, 

 but so brief is his description that I am not sure of any differ- 

 ence. I therefore prefer to leave it under that species for the 

 present. 



Southampton, Mass., 1878. Eather common. 



