18 Mr. Lubbock on 



Seen from above this species is narrow in proportion to its length. 

 The anterior antennae are short, being about equal to the cephalo- 

 thorax in length. The posterior penultimate and antepenultimate 

 setae are the longest, then the anterior penultimate and that of the 

 third segment ; few of tl)e rest are equal to the segments in length. 



The two branches of the second pair of antennae are nearly 

 equal in size, but the accessory branch is rather larger than the 

 other, and has eight long hairs along its outer margin. 



The teeth of the mandible are small, and nine in number, be- 

 sides the usual spine. The outer branch of the palpus has six 

 long plumose hairs ; the inner one has twelve, four of which are 

 situated on a prominence at the side, and four more along the 

 margin. 



The first and second pair of maxillae and maxillipeds are formed 

 as usual. 



The branches of the natatory legs are three-jointed. In the first 

 pair the basal segment of the inner and lesser branch bears one 

 hair, the second segment two, and the third eight, of which two 

 are on the outer margin, four on the inner, and two at the apex. 

 The larger and external branch has one hair on the second seg- 

 ment, and five on the apical, besides the long terminal spine. In 

 the fifth pair of legs the second segment of the smaller branch has 

 only one hair, and the apical segment eight, three on each margin 

 and two at the apex. The terminal segment of the larger branch 

 has only four hairs, besides the terminal spine. 



Abdomen four-jointed, segments gradually decreasing in size. 

 The caudal setae were in every case broken off, but from the size 

 of the stumps they appear to be of the usual length. 



Total length, -12. 



Collected in the Atlantic, 35'' 10' S. L. ; 18° 4' E. L. 



PI. III. 



Rhlncalanus cornutus, Da. 



Professor Dana found only four or five specimens of this beau- 

 tiful species, and does not mention whether they were males or 

 females. I also had only a few specimens, and all of mine had 

 the abdomen two-jointed, while in his it was four-jointed. The 

 antennae also differ from his description. My specimens may 

 therefore perhaps belong to a new species, but they agreed so 

 closely with R. cornutus, except in the above particulars, that I 

 did not like to describe them as new. 



Collected by Dr. Sutherland, N. L. 27° 30', W. L. 20°. 

 „ Professor Dana, „ 1° „ 18°. 



