FEOM THE GTJLF OF GUINEA. 71 



N., long. 3° 42' W., 50 fathoms, January 13tli (day collection). Lat. 3° 55' 3" N., long. 

 4° 7' 3" E., 30 fathoms, January 20th (day collection). Off Sao Thome Island (lat. 0" 34" 

 N., long. 6'' 31' 6" E.), 20 fatlioms, January 23rd (day collection). Station 3, 135 fathoms, 

 Fehruary 5th (day collection). 



JEtidius armatus occurred in 19 toAV-nettings, all of which -were under-surface col- 

 lections and ranged in depth from 5 to 460 fathoms ; 2 of the tow-nettings were collected 

 during the night, the other 17 were day collections. With one exception, all the 

 tow-nettings were from 20 fathoms or more, and eleven of them from 50 fathoms and 

 over. The difference between the bathymetrical distribution of this species and of Acartia 

 denticornis is very marked, the Acartia having been observed only in surface gatherings. 

 The distribution of ^tidius was nearly coextensive with the area examined, aud 

 in some of the tow-nettings it was of comparatively frequent occurrence. The strong 

 curved rostrum, and the sj)inous and strongly produced lateral angles of the last 

 thoracic segment, are so conspicuoiis as to make the species readily distinguished from 

 other Copepoda. It was obtained at five of the ' Challenger ' stations, one of which 

 (Station 348, lat. 3 10' N., long. 14 51' W.) was in the vicinity of the area traversed by 

 the ' Buccaneer.' 



iETiDius ARMiGER (Gicsbrecht). (PI. VIII. figs. 16-27.) 



1892. Gaetanm armiger, Giesbrecht, Fauna und Flora des Golfes von Neapel (Copepoden), p. 224, 

 pi. xiv. figs. 19, 20, 22, 26, 28, pi. xxxvi. figs. 2, 6. 



Female. Length, exclusive of tail-setae, 2*6 mm. (about 1-lOtli of an inch). The male is 



rather smaller than the female. Body robust, composed of four segments, the first 



segment more than twice the entire length of the other three, rounded anterioi-ly and 



furnished with a prominent sharp-pointed rostriim. The postero-lateral angles of the 



last thoracic segment are produced backward into spiniform processes as long as the 



first abdominal segment. Anterior antennae reaching to the extremity of the abdomen, 



alike in both sexes, and composed of 24 joints, which are sparingly setiferous ; the 



prof brtional lengths of the joints nearly as in the formula : — 



!) ■ (i ■ 3 ■ 3 ■ 3 ■ 3 ■ 4 ■ ■ .3 ■ .3 . 4 ■ 6 ■ .5 ■ 6 . 7 ■ 7 ■ T ■ t) ■ 8 ■ 7 . 8 ■ 8 . 7 . 3 

 1 1' 3 4 5 (i 7 8 'J 10 11 12 13 14 1-5 16 17 18 19 20 21 22 23 24' 



The basal joint of the posterior antennte wants the three setae shown in Brady's figure 

 of u'Etidiiis armatus ; the first joint of the secondary branch is small, the second larger, 

 the third, fourth, and fifth small and bearing each a long plumose seta ; the sixth joint 

 is fully one third the length of the whole branch, and furnished with one plain and three 

 long plumose terminal setae. Mandibles and maxillae as in ^E. armatus ; one of the two, 

 small intermediate digits of the maxilla-palp terminates in a spiniform plumose seta. 

 Foot-jaws also similar to those of ^TJtidius armatus, except that the two outer marginal 

 lobes of the anterior foot-jaw terminate each in a stout elongate spine, ciliate on the 

 inner edge ; and the inner distal angle of the basal joint of the second foot-jaw forms a 

 blunt, rounded process, the end of wliich is ciliate and bears a few setae (fig. 22). The 



