REPORT ON THE COPEPODA. 75 



branches of the first and second swimming feet, and the presence of a fifth foot in the 

 female, constitute other important points of distinction. But the most nearly allied genus 

 appears to be -one recently described by Dr. Giesbrecht, under the name Lucullus, in which, 

 however, the anterior antenna of the male is only nineteen-jointed, and there are but 

 four pairs of swimming feet in the female. 



Calanoides patagoniensis, n. sp. (PL XXIII. figs. 1-10). 



Length, 1-1 0th of an inch (2*55 mm). Rostrum bifid to the base, each branch very 

 slender and produced into a long filament. Anterior antennae about as long as the body, 

 slender, sparingly seliferous, the joints rather constricted in the male. Branches of the 

 mandible-palp (figs. 3,4) two-jointed, short. Second foot-jaw of the male (fig. 7) bearing- 

 two reflexed, densely plumose setae (as in Calanus). Swimming feet (fig. 8) slender, the 

 marginal and terminal spines long and slender. Fifth pair of feet of the male (fig. 9) 

 very long and slender, reaching considerably beyond the extremity of the abdomen, that 

 of the left side the longest, the second joint of each side bearing at its apex a short 

 rudimentary inner branch, which on the left side is one-jointed and almost obsolete, on 

 the right longer and three-jointed : the main branch of each limb ends in a long spine- 

 like seta. Abdomen in both sexes slender ; caudal stylets about as long as broad ; setse 

 subequal, the longest scarcely longer than the abdomen. 



Habitat. — This species occurred in some abundance in a surface-net gathering in 

 the South Pacific, lat. 46° 53' S., long. 75° 11' W. (Station 304). 



jEtidius, 1 n. gen. 



Cephalothorax composed of four segments ; head and thorax coalescent ; anterior 

 antennae twenty-four-jointed ; posterior antennae and mouth-organs (in the female at 

 any rate) like those of Calanus. Four pairs of feet only in the female ; five pairs in the 

 male, the fifth pair rudimentary, though composed of two branches. Inner branch of the 

 first pair one-jointed, of the second (indistinctly) two-jointed ; of the third and fourth 

 three-jointed. Abdomen of the male five- of the female four-jointed ; tail setae equal. 



In general structure this is very closely similar to Calanus, the only important dif- 

 ferences being found in the jointing of the inner branches of the swimming feet, bhe 

 absence of a fifth pair in the female, and the rudimentary character of those organs in the 

 male. The mandibles and foot-jaws are small, but I have not observed whether their 

 characters materially differ in the two sexes. I have seen, I think, only one or two 

 males, and my examination of them was made before I was aware of the great importance 

 of sexual characters in these parts. 



1 titrioev;, eaglet (from the strongly-hooked rostrum). 



