FEOM THE GITLF OF GUINEA. 73 



composed of 23 joints, the proportional lengths of the joints being nearly as shown in 

 the formula : — 



3.5.2.2.2.2.2.4.2.2.3.3.4.4.4.4. 4. 4.4.4.4.5.6 

 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 iTTS 19 20 21 22 23' 



The posterior antennae nearly as in Drepaiwjms pectinalas. Mandibles well developed, 

 strongly dentiferous on the biting-edge, and furnished with a large two-branched palp 

 one branch being 2-, the other '1-jointed (fig. 29). Anterior foot-jaws 4-jointed, the last 

 two very small; marginal lobes six, tive of tliem large, each with two (or three) plumose 

 terminal setae; the other small, forming the base of a single plain seta; three plain 

 sette spring from the last joint of this foot-jaw. The posterior foot-jaws are 7-jointed ; 

 the first and second joints are large, subequal, and longer than the entire length of the 

 next three ; the third to the last joints are small and furnished with a few plumose hairs 

 (fig. 31). First pair of swimming-feet similar to those of Drepanopus pect'matits, but 

 there are longer spines on the outer distal angles of the first two joints of the outer 

 branch, and the inner distal angle of the second basal joint tei'minates in a short spine 

 instead of a plumose hair. The three following pairs are also similar to Drepanopvs 

 pectinatus, except that the distal margin of the second basal joint is strongly denticulated 

 in the second pair, and in the third 2iair is furnished with a few large spiuiform teeth ; the 

 tei'minal spines of the outer branches are long and broad, and finely serrate on the outer 

 margin. The fifth pair are robust, simple, and composed of two 2-jointed branches of 

 unequal length ; in the short branch the last joint is much smaller than the other and 

 terminates in three conical tooth-like prolongations ; in the other branch, which is at 

 least twice the length of the short one, the last joint is rather longer than the first, and 

 bears a small spine near the middle of the outer margin and three spiniform teeth at the 

 extremity (fig. 35). The abdomen is composed of four segments, the first longer tlian 

 the others, the next two subequal, the last small. Caudal stylets about as long as the 

 last abdominal segment and bearing four plumose terminal hairs. 



Habitat. Lat. 1° 55' 5" N., long. 5° 55' 5" E., 35 fathoms. 



One specimen only of this species has been obtained ; it appears to be a female. While 

 agreeing with Drepanopxis in its more important details of structure, Clausocalanus 

 latipos differs from both the species described in the Report on the ' Challenger ' 

 Copepoda, especially in the number and proportional length of the joints of the anterior 

 antennae autl in the form of the fifth feet. It agrees in some respects with Clausocalanus 

 furcatus, Brady, but in that species, the inner branches of the second pair of swimming- 

 feet are 1-jointed, the fifth pair and the anterior antennae also differ cousideraljly, so 

 that for the present it seems better to consider the species as distinct. 



Clausocalanus aecuicornis (Dana). (PI. VIII. figs. 38-47.) 



1849. Calanus arcnicornis, Dana, Amer. Journ. Sc. vol. viii. 



1892. ClauavcaJa litis arcuicornis, Giesbrecht, op. cit. p. 193, pis. ], 2, 10, 3G. 



Length, not including tail-setae, 1-3 mm. Body elongate, composed of five segments, 



SECOKD SEIUES. — ZOOLOGY, VOL. VI. 10 



