96 TWELFTH ANNUAL REPORT. 



Sp. 5. Alona lineata, Fischer. 



Lynccim Uneatus, fischkr, leydig. 



Alona lineata. schoedlrr, p. e. muelleb, kukz. 



Mona rectangular is, sars. 



The upper margin is rouuded, the lower one somewhat sinuate, 

 with setae of moderate length. The beak is tolerably long, reach- 

 ing nearly to the level of the lower margin of the shell; the pig- 

 ment fleck is less than the eye, to which it is much nearer than to 

 the end of the beak. Post-abdomen short, broad and tapering 

 toward the end, truncate, armed with about ten large teeth; 

 caudal claws with a small basal tooth. Shell marked with distinct 

 lines running horizontally. The ephippial females are recognized 

 by a deep color and the greater elevation of the back. Length 

 0.5 mm., 0.6 mm. The male has a weak hook on the first foot, and 

 the post-abdomen is narrowed toward the end; the terminal claw 

 has no spine. 



The Minnesota representative of this widely distributed species 

 differs in some respects. The lower margin is nearly straight'and 

 rather sparsely hairy; the beak is blunt, but, on account of the 

 spreading of the extremely wide fornices, does not appear so except 

 under pressure. 



The beak reaches nearly to the lower shell margin. The 

 antennules are narrow, one or more of the setse being elongated^ 

 The dorsal margin is either nearly straight or strongly arched 

 behind; in either case the greatest hight of the shell is back of the 

 middle. The pigment fleck is large. The post-abdomen is just as 

 in A. lineata, but the lateral row seems to be of spines rather than 

 fringed scales. The shell is marked by rather evident or indistinct 

 lines. The form agrees pretty well with Schoedler's figure, except 

 that the posterior shell margin is much higher. The antenna3 

 have eight setae, but the last one is very weak. The terminal 

 setae seem sometimes to be spined, as figured byi,Schoedler, but in 

 some specimens they are perfectly smooth. There is a circlet of 

 spines on the second joint of the setose ramus. There is a hair on 

 the inner aspect of the protuberance of the labrum. The eye is 

 somewhat nearer the pigment fleck than is the end of the beak. 

 If it is desirable to apply a new name to a form at least so^near the 

 European A. lineata, it may bear the name£first given it in ray 

 note-book. 



