FEOM THE GULF OF GUINEA. 41 



outwards. The terminal spines of the outer branches of the first pair are more slender 

 than those of the others ; all tlie four pairs are furnished Avith numerous stout plumose 

 seta? on the inner marorins of both branches as well as round the extremity of the inner 

 branches. The fifth pair in the male is 1-branchcd. The second joint of the right foot 

 bears interiorly a small dilated process liaving a number of small spines ; the extremity of 

 the last joint truncate ; an elongate curved appendage with a tumid base springs from 

 the inner angle, and a stout setiferous spine from the outer angle of the extremity of 

 the last joint. The second joint of the left foot has a long slender appendage, very 

 faintly serrate on the inner edge. The outer angle of the third joint and the extremity 

 of the fourth terminate in a long spinous process, and the inner edge of the base of the last 

 joint is ciliated. The fifth pair in the female is 1-branched, the right and left are 

 similar, and 3(or 4 ?)-jointed ; the first and second joints stout, the third short, but produced 

 inwards into a large curved spiniform process, finely but distinctly serrate on both 

 margins ; the last (?) joint nearly obsolete, terminating in one long plain spine and a second 

 short one, serrate on the inner edge. Abdomen (exclusive of caudal stylets) nearly half 

 as long as the cephalothorax, 5-jointed in the male, 4-jointed in the female ; the 

 second, third, and fourth segments in the male, and the first, second, and third in the 

 female, fringed posteriorly wdth a prominent row of saw-like teeth. Caudal stylets as 

 long as the last abdominal segment, narrow, somewhat divergent, bearing each four 

 moderately long, terminal, plumose setva, and a fifth which springs from a notch on the 

 outer margin ; all the seta? are articulated below the proximal half; there is also a small 

 hair between the two inner setse. Ova forming one large circular complanate cluster, 

 containing about sixteen large ova arranged in a single layer, eleven or twelve round 

 the circumference, the others central. 



Habitat. Lat. 5° 10' N., long. 3° 56' 2" "W., surface, close inshore, January 12th (night 

 collection). Off Accra, three fathoms, January 16tb (night collection). Ofi' Appi, 

 surface tow-netting, January 18th (day collection). Libreville, Gaboon River, in two 

 surface tow-nettings, January 28tli (day collection). Bananah Creek, Congo River, surface 

 tow-netting, Eebruary 8th (night collection). 



Seterocalanus serricaudafus appears to be more confined to inshore waters than many 

 of the species recorded in this Report, though it seems nevertheless capable of existing 

 under varied conditions as regards the density of the water, having been obtained in 

 water varying in specific gravity from 1*02511 to l'0087O. 



Genus Pleuromma, Claus. 



Pleuromma, Claus, Die freilebenden Copepoden (1863). 



? Mctridia, Boeck, Oversigt af Norges Marine Copepoda, 1864. 



? Metridia, Brady, Monograph, British Copepoda, vol. i. 1878. 



Pleuromma abdominale, Claus. 



1863. Pleuromma abdominah, Claus, loc. cit. p. 195, pi. v. figs. 1-6, 13, 14; pi. vi. figs. 1-10. 

 1883. Pleuromma abdominak, Brady, ' Challenger,' Copepoda, p. 46, pi. xi. figs. 1-13. 

 SECOND SERIES. — ZOOLOGY, VOL. VI. 6 



