32 ME. T. SCOTT ON ENTOMOSTEACA 



feet, wliich is fully half as long as the next joint. The end of the last joint of the 

 outer hranch of the first pair is furnished with a stout plumose spinous seta, while the 

 outer hranches of the next three pairs have each a terminal falciform spine ciliated on the 

 inner margin and finely serrate on the outer margin. Fifth pair of feet 2-branched, 

 inner branch 1-jointed, rudimentary, and bearing at its apex a long plumose seta ; the 

 ff outer branch 2-jointed ; an extremely long slender seta springs from the outer edge near 



^ the proximal end of the second basal joint on both sides. The terminal joints of both of 



the outer branches bear several small spines on the outer margin and one on the inner 

 margin. Abdomen short, 4-jointed ; second and third joints smaller than the first, 

 subequal. Caudal stylets fully as long as the last abdominal segment, and furnished with 

 densely plumose dark-coloured setse. 



Bahitat. Lat. 6° 38' N., long. 12° 37' W., 25 fathoms tow-netting, January 6th (day 

 collection). One sj)ecimen only of this curious form was obtained. 



llliiihcalanus aculeatus differs somewhat from the generic characters of Rldncalanus as 

 described by Prof. Brady in the number of joints of the anterior antennge, the compara- 

 tively long terminal joint of the secondary branch of the posterior antennae, and in the 

 form of the mandible and maxilla, but agrees with the other characters ; I have therefore 

 included it in that genus. 



Genus Hemicalanus, Claus, 1863. 



Hemicalanus, Claus, Die freilcbenden Copepoden, 1863 (not Hemicalanus of Dana) ; 

 Brady, 'Challenger' Copepoda, 1883. 



Hemicalanus longicornis, Claus. 



1863. Hemicalanus longicornis, Claus, loo. cit. p. 179, pi. sxix. fig. 1. 

 1883. Hemicalanus longicornis, Brady, op. cit. p. 44, pi. ix. figs. 1-5. 



Habitat. Station 2, 25 and 50 fathoms, January 1st (night collection). Station 3, 100 

 fathoms (day collection). Station 9, 50 fathoms (day collection). Lat. 1° 55' 5" N., long. 

 5° 55' 5" E., 30, 260, 360, and 460 fathoms (day collections). Station 23, surface, and 10, 

 20, 85, 135, 185, and 235 fathoms, January 5th (day collections). 



Hemicalanus longicornis was obtained in 26 tow-nettings, but only one of these was 

 from the surface, all the others were under-surface gatherings and ranged in depth from 

 5 to 160 fathoms. 21 of these tow-nettings (including the surface gathering) were day 

 collections, while 5 were night collections, as shown in the formula : — 

 1 surface 1 day collection. 



25 under-surface I ^0 day coUections. 

 l 5 night ditto. 

 This Hemicalanus was of frequent occurrence in some of the tow-nettings. It was very 

 common in a gathering from 35 fathoms, collected on the 22nd January in lat. 1° 55' 5" 

 N., long. 5 55' 5" E. ; in this gathering eighty-five perfect specimens, besides a number 

 of others more or less damaged, were obtained. 



Tow-nettings 26. 



