3° 



DISCOVERY REPORTS 



Side-plate i slightly deeper than 2 and 3, rounded below, not expanded forwards; 

 4 deep and strongly excavate, contiguous with margin of anterior lobe of 5; posterior 

 !obe of 5 deeper than anterior lobe, hidden below 2nd joint of peraeopod 3 ; 6 and 7 

 ovate, deeper than long. 



Pleon segment 1 with antero-inferior angle quadrate, postero-inferior angle rounded ; 

 postero-inferior angle of segment 2 quadrate, of segment 3 shortly produced in a short 

 acute point, margin above straight; dorsal profile of segment slightly gibbous. 



Telson longer than basal width, cleft to base, lobes tapering evenly to acute apices, 

 smooth, without any spinules. 



Fig. 3. Shackktonia robusta, Brnrd. a. General view, punctuation indicated on segment 4. b. Profile of 

 epistome and upper lip. c. Maxilla 1. d. Maxilliped. e. Peraeopod 5. /. Pleon segment 3 of young (St. 123). 



Antenna 1, 1st joint large and stout, slightly produced on inner upper apex, 2nd and 

 3rd joints very short, flagellum 9-jointed, accessory flagellum nearly as long as flagellum, 

 6-jointed. Antenna 2 slightly longer than antenna 1 , 5th joint shorter than 4th, flagellum 

 u -jointed. 



Epistome convex in front, passing evenly into the upper lip, without any deep inter- 

 vening groove or notch. Mandible elongate, cutting edge straight, with denticle at each 

 end, oblique, secondary cutting plate and spine row obsolete, molar weak, conical, palp 

 inserted just behind molar, 3rd joint shorter than 2nd, falcate, a comb-like row of spine 

 setae on margin of 3rd joint and distal half of 2nd joint. Lower lip with lobes apically 

 subacute. Maxilla 1 slender, inner lobe feeble, tipped with 1 seta and 1 setule, outer 

 lobe strong, apex oblique, with six strong hook-like spines, followed by a comb-like row 

 of short spinules, palp 2-jointed, 2nd joint not quite reaching apex of outer lobe, 

 tapering distally to a subacute apex, with one minute spinule, another minute spinule 



