18 BIOLOGICAL SURVEY OF 



Cytheretta tracyi spec. nov. (fig. 9) 



The shell has the dorsal and ventral margins quite straight 

 and nearly parallel. The angle between the dorsal and pos- 

 terior margins is more marked than in C. edwardsi. The 

 inner shell margin is slightly sinuous and distant from the 

 outer margin. 



The right first leg of the male appears to consist only of 

 four joints, the second and third being fused. The penulti- 

 mate joint is two and a third times as long as the distal 

 joint. It is evenly rounded distally. There is a conspicuous 

 seta on the anterior margin. The distal joint is distinctly 

 constricted at the base. 



Length : Male, 1.38 mm. 



Type : Male, B 157 ; paratypes, B 146. 



Remarks: It gives me great pleasure to dedicate this in- 

 teresting species to Dr. Henry C. Tracy, of the Biological 

 Survey of the Mount Desert Region. 



This species shows a closer general resemblance to Cyther- 

 etta edwardsi (Cushman) than to C. rubra G. W. Miiller in 

 the great asymmetry of the first legs of the male. It differs 

 from both in having the depression in the inner shell margin 

 below the adductor muscle very shallow. 



