COPEPODA FROM IFALUK ATOLL 105 



Exopodite of leg 5 with 3 apical setae, in addition to a seta at the external 

 margin; no transverse rows of spinules S. major (T. Scott) 



4. External seta at basis of leg 2 of strongly increased size, present as a large, 



setiform spine 5 



External seta at basis of leg 2 normally developed, fine or absent .... 8 



5. 2nd endopodal segment of leg 2 as long as wide 6 



2nd endopodal segment of leg 2 longer than wide 7 



6. Body reddish brown, cephalon usually of a light, horny color. 



S. arthuri Poppe 



Body of a very light, transparent horny color, with a deep purple band on 



2nd thoracic somite and on abdomen. Usually bigger than preceding 



form S. arthuri var. magnum Monk 



7. Small (0.45 mm.) species, 3rd antennular segment short. Leg 5 with 6 



transverse rows of spinules on exopodite. 2nd segment of exopodite leg 



2 not spinulose. Color unknown S. dentipes, new species 



Bigger (0.65-0.68 mm.) form; 3rd antennular segment long, only slightly 

 shorter than 2nd segment. 2nd segment of exopodite leg 2 spinulose. 

 Leg 5 with 5 transverse rows of spinules on exopodite. Body of a light 

 horny color; thoracic somites 2 to 4 and basal parts of legs purple. 



S. piirpurocincta Monk 



8. 1st segment of exopodite leg 1 as long as 1st segment of endopodite. 



S. ligusticum (Brian) 

 1st segment of exopodite leg 1 much shorter than 1st segment of endop- 

 odite 9 



9. 2nd segment of endopodite legs 3 and 4 with 1 seta . S. hippolytes (Kr0yer) 

 2nd segment of endopodite legs 3 and 4 with 2 setae 10 



10. Exopodite of leg 5 with only 1 terminal seta, remaining setae marginal . . 12 

 Exopodite of leg 5 with at least 3 terminal setae 11 



11. Baso-endopodite of leg 5 with 3 setae S. idyoides (Brady) 



Baso-endopodite of leg 5 with 2 setae 12 



12. Exopodite of leg 5 inserting with broad base, internal and external wall 



nearly parallel, so that segment is elongate . . S. cockburni Fairbridge 



Apical part of exopodite leg 5 narrowed, inserting with small base; internal 



and external margin convex, segment ovate . . . S. australe (T. Scott) 



13. Exopodite of leg 5 with 2 short, thick setae, 1 at terminal, 1 at external 



border. In addition there are marginal spinules and transversal rows of 



spinules S. fucicolum (T. Scott) 



Exopodite of leg 5 with 5 distinct setae 14 



14. Spines at external margin of 3rd exopodal segments legs 2 to 4 lancet- 



shaped 16 



Spines at external margin of 3rd exopodal segments legs 2 to 4 not lancet- 

 shaped 15 



15. Coxa of maxillipede with strong internal spine. Apical seta exopodite leg 



5 lengthened S. loureiroi Jakobi 



Coxa of maxillipede without spine at internal margin. Apical seta of 

 exopodite leg 5 short S. longicauda (Philippi) 



16. 2nd exopodal segment of leg 1 swollen. 2nd endopodal segment of leg 1 



more than twice as long as wide 17 



2nd exopodal segment of leg 1 not swollen, 2nd endopodal segment of leg 1 

 only V/2 times as long as wide. Exopodite of leg 5 broad, with 5 transverse 

 rows of spinules S. lamellipes Monk 



