FROM THE GULF OF GUINEA. 67 



The male right antenna is 17-joiute(l ; the 11th, 12th, and 13th appear to be each 

 composed of two coalesced joints, indistinctly hinged between the 12th and 13th joints, both 

 of which are ciliate on the upper margin. On the proximal side of the hinge there is 

 one and on the distal side three short stout spines, as shown in fig. 8. Posterior antennae 

 and mouth-organs as in Faracartia spinicaiidata. The length of the joints of the inner 

 branches of the first pair of swimming-feet is about equal, while the first joint of the 

 outer branch is mvich stouter and once and a half the length of the next. The 

 inner branch of the fourth pair is slender, the first joint of which reaches nearly to the 

 middle of the second joint of the outer branch; the last joint of the outer branch is 

 much smaller than either of the other two joints ; the terminal spines are long and slender 

 (fig. 27). The fifth pair in the female are each furnished with two long setae, one of 

 which is submarginal and plumose and one apical ; the basal part of the plain apical seta 

 is considerably dilated and gibbous (figs. 29, 30). The right fifth foot in the male is 

 much longer than the other, and the penultimate joint, which is shorter than either the 

 preceding or following joints, is produced interiorly into an elongate protuberance ; the 

 last joint of the left foot is armed with a large spine on its inner aspect ; each foot termi- 

 nates in a short stout spine, and the first joint of both is furnished with a long plum se 

 seta on the outer margin (fig. 30). In the abdomen of the female the first segment is 

 about once and a half the length of the next and fully twice the length of the last 

 segment ; the first and second segments are sparingly dentate on the posterior margin 

 (tig. 31). Caudal stylets longer than the last, and nearly as long as the penultimate, 

 abdominal segment ; caudal setae as in Acartia Clausi. The first segment in the male 

 abdomen is considerably narrower than those that follow. The caudal stylets are about 

 three-fourths the length of those of the female and not longer than the last abdominal 

 segment, and furnished with setae as in the female (fig. 32). 



Habitat. Bananah Creek, Congo River, in a surface gathering collected at noon, 

 Eebi'uary 7th; the specific gravity of the water when the gathering was made was 

 1"00870 ; and in Loanda Harbour, in two surface gatherings collected in the seaward part 

 of the Harbour during the afternoon of the loth February. The surface temperature 

 of the water was about 79° P. 



Acartia plumosa somewhat resembles Acartia discandata (Giesb.), especially in the 

 male right anterior antennae and fifth pair of feet, which are quite prominent in adult 

 specimens. 



Acartia Clausi, Giesbrecht. (PL VII. figs. 33-40.) 



1889. Acartia Clausi, Giesbreclit, Rendicouti R. Accad. d. Liucei, vol. v. fasc. 11. 

 1892. Acartia gahoonensis, Scott (MS. name). 



Length fully 1 mm. Viewed doi'sally the body is oblong-ovate, the forehead is broadly 

 triangular, almost truncate, with the lateral angles somewhat produced ; the last thoracic 

 segment has the postero-lateral angles rounded. Anterior antennae nearly as long as the 

 thorax, those of the female, which are 21-jointed, are sparingly setiferous, except towards 

 the extremity, where the last five joints bear moderately long plumose setae ; a plumose seta 



9* 



