DESCRIPTION OF SPECIES 343 



The form of the second, third and fourth thoracic appendages is shown in the figures 

 (Fig. 17 c-e). The second appendage is stout; the propodus is oval in shape, and bears 

 on its inner margin a row of about thirty-six rather delicate spines which appear to be 

 simple but with a high magnification show fine, short pectinations near their distal ends. 

 The spines are of two lengths, the longer being slightly stouter and alternating with the 

 shorter type. The species agrees with S. exigiia and differs from all other species in 

 having only one variety of modified spine on this joint. At the proximal end, the inner 

 surface is considerably raised into a median prominence, and its steep face (towards the 

 distal end of the joint) is covered with very short hairs ; the dactylus extends for some 

 distance beyond the flat face of this raised area. 



The distal truncate extremity of the carpus bears two stout spines, each with a bifid 

 extremity, and three or four delicate setae. The third appendage of the male (Fig. 17 d) 

 is longer but less robust than the second. The propodus is broad and its inner margin 

 is armed with a double row of five modified setae of the usual type ; near its proximal 

 end is a small group of short hairs and at the outer angle of its truncate distal extremity 

 is a group of five long setae : the dactylus terminates in a stout spine at the base of which 

 are a few short hairs. The setae present on the remaining joints as well as those of the 

 other appendages are long, usually simple, and arranged in short transverse rows in 

 notches on the margins of the joints (Fig. 17 e). The last thoracic appendage is similar 

 in the two sexes ; it is shorter than the others, and its joints are relatively broader in 

 proportion to their length. 



The protopodite of the first three pairs of pleopods is somewhat triangular in shape 

 with the produced angle bearing long plumose setae ; there are three of these on the first 

 and two on each of the second and third pleopods. The appendix masculina on the second 

 pleopod of the male reaches about two-thirds of the way towards the apex of the terminal 

 segment. Both the exopod and endopod of the fourth pleopod are divided by a trans- 

 verse suture ; the outer margin of the exopod is fringed with plumose setae. 



The protopodite of the uropod (Fig. 17/) is rather long, with its inner angle produced 

 and bearing a short plumose seta; the exopod is shorter than the endopod, and both 

 are fringed along their inner margins with long plumose setae which, however, do not 

 extend quite to their distal ends. 



Distribution. This species was collected from localities north and west of the 

 Falkland Islands, in water from 98 to 150 m. in depth. 



29. Serolis pagenstecheri, Pfeffer. 



S. pagenstecheri, Pfeffer, 1887, p. 73, pi. ii, figs, i, 2, pi. iv, figs. 1-3; Tattersall, 1921, p. 231 ; Monod, 



1931, p. 26; Nordenstam, 1933, pp. 85-8, text-figs. 

 S. pagenstecheri var. albida, Nordenstam, 1933, pp. 88-9, pi. i, figs. 4, 5, text-fig. 21 e. 



Occurrence. St. 39: South Georgia, 179-235 m.; i ? (b.), 2 3S (immature). 



St. 42: South Georgia, 120-204 m.; i ? (b.); 2 ?? (non-b.), 2 immature <J<J, and a number of 



small specimens. 



St. 140: South Georgia, 122-136 m.; a number of immature specimens. 



St. 144: South Georgia, 155-178 m.; 4 immature specimens. 



