(16) 



inner inferior angle of the second joint. The body of this species is broader 

 than in D. caUor, the color is throughout a deep red. The antennae are 

 nearly as long as the body, the eighteenth joint in the female reaching to the 

 base of the abdomen. The second tooth of the mandible is larger than any of 

 the remaining six of the series, and is separated from the third by an interval 

 equal to the width of the tooth. A short feathered bristle appears at the 

 lower end of the row of teeth. The secondary appendage of the mandibular 

 palpus is four-jointed, and bears six bristles at its tip and inner margin. 

 The maxilla has the normal structure, the basal plate, the two cylindrical 

 processes and the outer ramus (flabellum) and the inner ramus being all 

 present and symmetrically developed. The first maxilliped is nearly as 

 broad as long, and bears 15 long hairs on its margin. The basal segment of 

 the second maxilliped presents four rounded processes on its inner margin, 

 of which the first is smallest and bears one bristle, the second and third are sub- 

 equal and bear respectively two and three bristles, and the fourth is largest, 

 is much produced inferioriy (the rounded lower end being finely ciliate) and 

 bears four bristles. 



The fifth pair of legs in the female is bi-ramose, the inner branch 

 straight, slender, not jointed, terminating in two short claws; the outer 

 strong, two-jointed, terminating in a single slightly serrate claw. The sec- 

 ond joint of this branch bears two slender bristles near the middle of the 

 outer margin, otherwise the leg is destitute of hairs and spines. The legs of 

 the fifth pair in the male are very dissimilar. The right leg consists of five 

 joints ; the basal quadrate ; the second about twice as wide as long, en- 

 larging distally and bearing a strong blunt spine at the inner, and a longer 

 one at the outer, inferior angle. The third joint is sub-quadrate, the fourth 

 clavate, bearing a long bristle at the middle of its outer mai'gin ; and the 

 fifth constitutes a slender incurved dactyl as long as the preceding joint, 

 slightly serrate on the distal half of its inner margin, and so jointed as to 

 close back against the inner margin of the fourth joint, which thus acts as 

 a hand. The left leg reaches about to the tip of the third joint of the right, 

 its pedicel contains two large quadrate joints ; the outer ramus two small 

 joints, of which the terminal one is forcipate at the tip, the inner ramus a 

 single slender joint on which no armature was seen. The /«rca bears at 

 tip of each branch four long feathered hairs, and a fifth smaller simple one 

 at the posterior internal angle. A sixth large and plumose hair is borne at 

 the posterior third of the outer margin. 



Found rather abundantly in a pool fed by a slow spring, ia March and 

 April, at Normal, Illinois. In several characters, especially those of the 

 mouth appendages, this species seems closely allied to Ichthyophorba, bear- 

 ing to some species of that genus a much closer resemblance than to D. 

 castor, if the figures in Baird's British Entomostraca are at all to be relied on. 



