418 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. xxxv. 



First maxillary process with six broad spines, which are faintly 

 ciliate at tip (fig. 7). Right maxillary foot of male (fig. 3) with a 

 sickle-like terminal claw, which is about two-thirds length of ter- 

 minal segment. Left maxillary foot much shorter, with a strong 

 sickle-like terminal claw, which is about four-fifths length of terminal 

 segment. Outer distal angle of terminal segment with a strong pro- 

 tuberance. 



Terminal spine of first foot strong, about three times length of 

 terminal segment, or about same length as penultimate segment. 

 Second segment broad, with a tuft of hair on the curved dorsal edge, 

 also a plumose seta on its dorsal distal margin which reaches to the 

 end of the following segment. The third segment is two-thirds 

 length of the following one, with a decided angular projection at its 

 proximal dorsal edge, and a short seta at its distal dorsal edge, which 

 is about two-thirds length of the following segment. 



Terminal segment of the second foot very small, about as long as 

 broad, about one-eleventh as long as preceding segment, and with 

 three setae of unequal lengths, two of which are terminal, and extend 

 in the direction of the length of the foot; the third, subterminal and 

 pointing in the opposite direction (fig. 5). One terminal seta about 

 three-fourths length of longer one, which is seven-eighths length of 

 penultimate segment; the remaining or subterminal seta being about 

 the length of the longer one of the three. 



Furca strongly bent (fig. 8), with two terminal bristles in place of 

 the usual terminal claws of the Cyprididse, these bristles being nearly 

 the same length, the shorter about three-fourths length of the longer 

 one, which is slightly more than two-thirds length of the posterior 

 or dorsal edge of the furca ; the'dorsal bristle situated less than width 

 of furca from subterminal bristle, and about two-thirds length of 

 same. The anterior bristle, corresponding to the usual terminal 

 seta of the Cypridida?, is entirely lacking. The furca of the female is 

 hardly so much bent as that of the 'male, but otherwise nearly 

 similar. 



The specimens studied by me were collected from the dune ponds 

 of the southern shore of Lake Michigan, near Clarke Junction, 

 Indiana. This is a typical undrained swamp region, with many 

 peat bogs. The ponds were originally formed between established 

 dunes, and in most cases are but relicts at present, having been 

 destroyed by successive encroachments of different types of vegeta- 

 tion — first bulrush (Scirpus), sedge (Carex), willow (Saliv), and 

 the grasses. The filling-in process has usually been accelerated by 

 abundant growths of Cham, the water lilies Castalia and Nymplwcn, 

 and Utricularia. These were all found in great abundance in this 

 region. Among the marginal plants noted were the swamp cinquefoil 

 {Potentilla palustre), buckbean (Menyantkes trifoliata), and the 



