NO. 3 COPEPODA FROM PANAMA MARSH II 



second abdominal segment is very short being only about one-fourth 

 the length of the third. 



The third segment and the furcal rami are about equal in length. 

 The furcal rami are ciliated on the inner margin. The egg sac of the 

 female has about 16 eggs. 



The antennas reach the end of the furca. The right antenna of 

 the male is swollen anterior to the geniculating joint ; the antepenulti- 

 mate segment has no special armature. 



The spines of the first basal segments of the fifth feet of the female 

 (pi. 3, fig. i) are stout and blunt. 



The lateral hair of the second basal segment is small. The first 

 segment of the exopodite is about three times as long as wide. The 

 second segment, with the hook is about as long as the first. The 

 inner margin of the hook is finely denticulate. The third segment is 

 distinct and bears two spines, the inner being about twice as long as 

 the outer. The endopodite is composed of a single segment in the 

 Guatemala specimens, but in the Panama material it is indistinctly two- 

 segmented ; it is about two-thirds as long as the first segment of the 

 exopodite and bears two spines near the tip. 



The spines of the first basal segments of the male fifth feet (pi. 3, 

 fig. 2) are of fair size and stout. The second basal segment of the 

 right foot is longer than wide, with a blunt projection on its inner 

 margin at about one-third its length. The lateral hair is small and 

 situated near the distal end of the segment. The first segment of 

 the exopodite is about two-thirds as long as wide, the outer margin 

 being considerably longer than the inner; it has an arcuate cuticular 

 ridge on the posterior surface near the distal end of the segment and, 

 projecting from this, a stout, blunt spine: back of this is a second 

 cuticular prominence of varying size. The second segment is about 

 as long as the second basal segment and has an elongated oval out- 

 line. The lateral spine is situated at about the middle of the seg- 

 ment, is slightly curved, and about equals in length the combined 

 lengths of the first and second segments of the exopodite ; the inner 

 margin of the spine bears five to seven blunt teeth. These teeth are 

 seen more distinctly in the magnified figure (pi. 3, fig. 3). This 

 dentate lateral spine is unique, not having been noted in any other 

 species. The terminal hook is falciform with a symmetrical curva- 

 ture, and in length about equals the rest of the foot exclusive of the 

 first basal segment. The endopodite of the right foot is triangular, 

 equalling in length the inner margin of the second basal segment 

 and is setose at the tip. 



