On Fresh-water Entomostraca. 35 



tained. It also occurred in the sample first received from 

 Prof. Ramsay, and taken from the Waterloo Swamps. 



Gen. Alona, Baird. 



15. Alona Whiteleggii, G. O. Sars, n. sp. 

 (PI. 6, figs. 1, 2). 



Specific Characters. — ^ Shell, seen laterally, oval 

 quadrangular, but very slightly widening behind, dorsal 

 margin evenly arcuate, ventral nearly straight, hind extremity 

 somewhat obliquely truncated, with the upper corner obso- 

 lete, lower rounded off. Head somewhat procumbent, ter- 

 minating in an acute rostrum. Surface of shell striated 

 longitudinally, ioferior edges densely ciliated. Ocellus almost 

 as large as the eye. Tail rather large, lamellar, though 

 scarcely widening distally, being obtusely truncated at the 

 tip, post-anal angle almost obsolete, posterior edge below it 

 very slightly convex, of ante-anal denticles about 15 pairs, each 

 accompanied by a squamiform lateral denticle, terminal claws 

 each with a rather strong secondary denticle at the base. 

 Length of adult female 0,63 mm. 



Remarks. —This form is somewhat intermediate in 

 character between the European species, A. qvadrangidaris 

 and oblonga, without being referable to either of them. In 

 size and sculpture it more resembles the first-named species, 

 but the form of the shell and that of the tail is rather dif- 

 ferent, and agrees more with that found in A. oblonga. I 

 have much pleasure in dedicating this beautiful species to 

 Mr. Whitelegge, to whom I am indebted for the greater 

 part of the material here treated off. 



