— 38 — 



established together with i new, hitherto misinterpreted, 

 antarctic species. 



A. Third or fourth abdominal segment with a good-sized, 

 compressed dorsal process from the hind margin. 



a. Third abdominal segment with a good-sized process 

 from the end of its strong dorsal keel, and small 

 dorsal processes or denticles on the three following 

 segments. Eyes considerably higher than broad, 

 with transverse constriction. Lateral margins of the 

 carapace with a denticle at the middle. First pair of 

 legs elongate and robust. T. longipes Brandt. 



b. Third abdominal segment without any process from 

 its strong dorsal keel, but a good-sized process on the 

 fourth segment and distinctly smaller processes on 

 the two following segments. Eyes a little higher than 

 broad, without constriction. Lateral margins of the 

 carapace without denticle. First pairs of legs slightly 

 or at most a little longer and somewhat stronger 

 than the second. T. spinifera Holmes. 



B. Third and fourth abdominal segments without dorsal 

 processes. 



a. Lateral margins of the carapace without any denticle, 

 a. Sixth abdominal segment much shorter than the 



sum of the tw^o preceding segments, with a strong 

 spine from its upper distal end. Rather large and 

 somewhat robust species. T. inermis Kr. 



ß. Sixth abdominal segment elongate, almost or fully 

 as long as the sum of the two preceding segments, 

 and without any spine from its upper distal end. 

 Slender and rather small species. 



T. longicaudata Kr. 



b. Lateral margins of the carapace. with a denticle. (No 

 spine from the upper end of sixth abdominal seg- 

 ment.) 



a. Denticle before the middle of the lateral margin of 

 the carapace. Eyes nearly circular, without con- 

 striction. First pair of legs not elongate, shaped as 

 the second. T. Raschii M. Sars. 



