27 / c 3 



rostrum to the posterior margin. The junction here is not well 

 marked, and at the lower corner the posterior margin does not 

 form a oharp angle with the ventral. The corner is rounded, but 

 on it are two strong teeth like those of Gr. testudinarius (Fischer). 

 The ventral margin is straight. The front half bears long, straight, 

 closely set, plumose setas, while those on the hinder part are shorter 

 and more scattered. The meshes of the reticulation are mostly 

 hexagonal on the head, quadrangular or irregular on the body. 

 The lines of the network in the front and lower part of the valves 

 radiate from the junction of valve and fornix. The first few rows 

 run to the ventral margin. The succeeding rows bend and run 

 parallel to that edge. Those on the upper half of the valves are 

 parallel to the dorsal margin, and there are one or two imperfect 

 rows in the middle of the valves where the two sets meet. The 

 upper set are continued on to the head, running around parallel 

 to the edge of the fornix. The lower, dorsal, margin of the post- 

 abdomen bends upwards just below the anus, and thus makes the 

 apex pointed. There are about eight clusters of three or four 

 hairs each, on each side. The terminal claws are small and un- 

 armed. The eye is only of moderate size, smaller proportionally 

 than in Alona. While in Alona the diameter of the eye, in an 

 average specimen may equal y 1 ^- of the total length, in Gr. inermis, it 

 equals only yt~tw °^ ^ ne length. The macula nigra is about 

 two-thirds as large as the eye, a little smaller than in Alona. 

 Male not seen. 



This species resembles Gr. testudinarius in most particulars (see 

 the excellent description of this species. Kurz, 1. c, pp. 50-53). 

 The differences are, the eye in this species is small instead of 

 large ; its shape is rounded, not " nearly triangular ;" the macula 

 nigra is not greatly smaller than the eye ; the terminal claws are 

 smooth and not "ornamented with teeth;" there is no trace 

 of an elevation on the back, where the outline of the head meets 

 that of the back; the posterior lower corner is rounded, though, 

 armed with teeth, and not prolonged into a sharp angle. 



The outline in general more closely resembles that of Gr. reticu- 

 lars than that of Gr. testudinarius. In most respects, however, it 

 more closely approaches the latter species. 



