NO. 3 COPEPODA FROM PANAMA MARSH J 



The antennae are composed of 21 segments, and about equal in 

 length the cephalothorax. The part of the male right antenna 

 beyond the geniculating point is composed of two segments. 



In the fifth feet of the male the first basal segment of the right 

 foot is short (pi. 2, fig. 3) as broad as long and has on its inner 

 margin a few very short spines. In the second basal segment the 

 length is to the breadth as four to three ; it has a patch of rather short 

 spines near its inner margin and a small lateral hair on the outer 

 margin at about two-thirds its length. It has a row of spines in the 

 distal margin of the anterior surface. The first segment of the ex- 

 opodite is about as broad as long. The outer distal angle is prolonged 

 into a dentate process. The inner margin is armed with two or 

 three rows of stout spines and upon the posterior surface not far 

 from the inner distal angle is a large spine. The second segment of 

 the exopodite is about equal in length to the second basal segment. 

 The outer margin is convex, while the inner is slightly concave. The 

 distal end is about twice as broad as the proximal. The lateral spine 

 is near the distal end, is straight, acute, and about as long as the first 

 segment of the exopodite. Nearly opposite the lateral spine there 

 is, on the inner margin, a short hair. The terminal hook is symmetri- 

 cally curved, denticulate on the inner margin and somewhat shorter 

 than the rest of the exopodite. It has two short spines near the 

 proximal end. There is no endopodite on the right foot. 



The second basal segment of the left foot (pi. 2, fig. 2) is not 

 quite twice as long as broad, is quadrangular in general outline, and 

 bears two small lateral spines a little beyond its middle. It has a row 

 of spines on the distal margin on the anterior surface. The first 

 segment of the exopodite is quadrangular, broader than long, and 

 bears a stout spine at its outer distal angle. On the distal margin 

 on the anterior surface is a row of spines. The second segment is 

 twice as long as the first. About midway of its length it has a stout 

 spine on the outer margin, and opposite this a small one on the inner 

 margin. The distal margin is setose. At the inner distal angle is 

 a stout serrate spine, and another similar spine near the inner margin 

 at about three-fourths the length of the segment. The left endopodite 

 is club-shaped, setose at tip, with two somewhat long setae, and ex- 

 tends about one-third the length of the second segment of the ex- 

 opodite. Length 0.1 mm. 



The female of this species is unknown. In connection with the 

 males two immature females were found. One certainly did not 

 belong to this species. The other probably did, but was too immature 

 to make a description possible. 



