SCIII/.oi'ODA. 17 



the spine, at any rate in this species, developes late in life, only after the final adult 

 form is reached. 



The species was taken on the homeward voyage of the ' Discovery,' in the 

 extreme southern part of the Pacific Ocean between New Zealand and Cape Horn. 



SUB-FAMILY NEMATOSCELIN.E, Holt and Tattersall. 



GENUS THYSANOESSA, Brandt. 



THYSANOESSA MACRURA. 



(PI. III., Figs. 1-12). 



Thysanoessa macrura, G. 0. Sars, 1883 ; id. (1885) ; Ortmanu, 1893 ; Stebbing, 1900 ; Holt and 

 Tattersall, 190(5 (l) ; Coutierc, 19m;. 



Localities of captures : 



Winter Quarters. 



No. 4 Hole, 47 specimens, 7-18 mm. 

 No. 8 Hole, 40 8-21 mm. 



No. 12 Hole, 2 7 and 20 mm. 



From River Koettlitz, 2. 1. 03, 6 specimens, 9-14 mm. 

 Outward or Homeward Journey. 



Lat. 61 46' S., long. 141 12' K, 16. 11. 01, 18 specimens, 14-20 mm. 

 Lat. 57 25' 30" S., long. 151 43' E., 20. 11. 01, 35 specimens, 12-22 mm. 

 Lat. 54 1' 15" S., long. 170 49' K, 27. 12. 01, 1 specimen, 6 mm. 

 Lat. 61 13' 30" S., long. 173 33' K, 31. 12. 01, 30 specimens, 12-19 mm. 

 Lat. 66 52' 9" S., long. 178 8' 15" K, 3. 1. 02, 3 specimens, 8-9 mm. 

 Lat. 70 29' 27" S., long. 168 51' 46" E., 26. 2. 04, 1 specimen, 28 mm. 

 Lat. 49 40' S., long. 172 18' 30" W., 12. 6. 04, 2 specimens, 8-12 mm. 

 Lat. 58 49' 45" S., long. 154 48' W., 24. 6. 04, 4 specimens, 10 mm. 

 Lat. 59 34' 30" S., long. 106 28' 12" W., 28. 6. 04, 3 specimens, 7 mm. 

 Lat, 55 44' S., long. 95 43' 30" W., 1. 7. 04, 3 specimens, 6-8 mm. 



Form. (Fig. 1) of the body rather slender. 



Carapace (Fig. 1) with a single rather long slender spine on the lower lateral 

 margin posterior to the middle, just above the origin of the sixth thoracic limb ; 

 antero-lateral corners acute and somewhat produced ; anterior margins very concave 

 and produced forwards into a long, slender, acute rostrum which reaches beyond the 

 eyes and far beyond the middle of the basal joint of the autenuules ; there is a low 

 keel on the anterior part of the carapace behind the rostrum, and a very faint 

 gastro-hepatic groove. 



Pleon (Fig. l) rather elongate, narrow and attenuate; segments unarmed; sixth 

 segment equal to or slightly less than the combined lengths of the preceding two ; 



