NO. 3 . COPEPODA FROM PANAMA MARSH 9 



The spines of the first basal segments of the male fifth feet (pi. 2, 

 fig. 4) are acute, with a prominent mammilliform base. The second 

 basal segment of the right foot is somewhat longer than wide ; the 

 lateral hair is situated at four-fifths of its length. The first segment 

 of the exopodite is ordinarily wider than long, and has a short cuticu- 

 lar ridg;e near its distal margin on the caudal aspect. The second 

 segment exceeds in length the combined length of the first segment 

 and the second basal segment, and is about twice as long as wide. 

 About midway of its caudal surface there are three cuticular ridges. 

 The lateral spine is situated near the distal end of the segment, is 

 stout and straight, finely denticulate on the margin, and is somewhat 

 shorter than the segment. The terminal hook is falciform, with a 

 nearly symmetrical curvature, finely denticulate on the inner margin, 

 and about equals in length the combined length of the rest of the ex- 

 opodite and the second basal segment. The endopodite is triangular 

 in form, not exceeding in length the first segment of the exopodite, 

 and has a few short setae near the tip of the inner margin. 



The left fifth foot of the male extends a little beyond the distal 

 margin of the first segment of the exopodite of the right foot. The 

 second basal segment is about four-fifths the length of the correspond- 

 ing segment of the right foot, is trapezoidal in shape, its distal margin 

 being about two-thirds as long as the proximal ; the lateral hair is 

 situated at three-fourths its length. The first segment of the exopodite 

 is about three-fourths the length of the second basal segment. It is 

 curved, the convexity being exterior, and bears a setose pad on its 

 inner surface. The terminal segment is nearly as wide as long, is 

 armed at the end with two small papilliform processes, and has on the 

 inner margin near the end a minute setose papilliform process. The 

 endopodite is triangular, about as long as the first segment of the 

 exopodite, and setose on the inner margin near the end. 



Length of female 1.48 mm. Length of male 1.31 mm. 



This was found in great numbers in a collection made in the Black 

 Swamp near the old line of the Panama Railroad. 



It occurred also in a pond at Bohio which had been there since the 

 time of the French excavations. 



DIAPTOMUS LEONINICOLLINUS, new species 

 A small species. The form and details of structure of the cephalo- 

 thorax and abdomen are like D. gatunensis. As in that species the 

 antenna? extend beyond the furca, and the antepenultimate segment 

 of the right antenna of the male has a hyaline lamella of the same 

 form (pi. 2, fig. 8). 



