52 CLEVE, PLANKTON FROM THE INDIAN OCEAN AND THE MALAY AKCHIPELAGO. 



slightly shorter than the left. Se short, somewhat behind the middle of the furca-. Si 

 issues from the interiör corner of the furca, as long as the distal part of the furca. 

 There is a small apicultis at the basis. St plumose, the 5^ 2 the longest, IV2 times as 

 long as the furca and as St 1 and 3 (both of almost equal length), 4 times longer 

 than St 4. 



Antennce of the 1st pair reach to the furca, 15-jointed. Aa 1~7, 9~10, 11~12, 

 13~14 and 24~25. Length of the distal joints in 0,ooö mm. 



Åa 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24-25. 

 13, 12, 18, 14, 18, 25, 18, 14, 25, 25, 12. 



Longest setaä on Aa 1~7, 9~10, 14, 16, 18, 21, 23 and on the terminal joint. The 

 S-p of Aa 23 and Aa 24~25 are plumose and a third as long as the antennse. The Si 

 of Aa 24~25 is delicate, but as long as the 2 last joints. 



Antennce of the 2nd pair as in the T. (Cori/nura) denticulata (Conf. Giesbr. Syst. 

 u. Faun. d. pelog. Cop., Pl. XXXI, fig. 6). 



The mandible as in C. forcipata (Giesbr., 1. c. lig. 3 and 5). Ri 2 carries 5 S. 



The maxilla exactly as in T. forcipata (Giesbr., 1. c. fig. 9). 



The maxillipeds of the 1st pair as in T. forcipata (Giesbr., 1. c. fig. 10). 



The maxillipeds of the 2nd pair as in T. forcipata (Giesbr., 1. c. fig. 7). 



Natatory legs of the 1st — 4th pairs. B 2 o{ the 1st pair as long as broad. Leg of 

 the 1st pair as in T. denticulata (Giesbr., 1. c. fig. 13). Se 3 on ii! 3 larger than Se 1 

 and 2. Si of the second joint of Ri on the 1st and 4th pairs 5 and of the 2nd and 

 3rd pairs 6. 



Fifth pair of legs neai-ly symmetrical, still, the left leg slightly longer than the 

 right. The teeth on the exteriör margin more distal than in T. forcipatus but other- 

 wise similar. 



Description of the male. Body. Length (anterior part 0,8, posterior O,?) 1,5 mm. 

 Anterior part 5-jointed, Th 4~5 uniting. Ahdomen 5-jointed; joints of nearly equal 

 length and somewhat broader than long. 



Antennce of the 1st pair. Right antenna geniculated. The distal part half as long 

 as the proximal, two-jointed, Aa 22~25 nearly twice as long as Aa 19~21. Exteriör 

 margin of Aa 19~21 finely denticulate, with 2 faint median S and 1 stronger distal. 

 Aa 18 as long as Aa 17 and half as long as Aa 19~21. Aa 17 with finely denticulate 

 margin, /la 15 with a small distal spine. 



Fifth pair of legs. B 1 of the left ;ind right leg and B 2 of the right uniting. 

 The left leg longer than the right, B 2 more than twice as long as broad, naked. Re 

 2-jointed. Re 1 with 1 rudimentary Se. Re 2~3 inside and proximally hairy, distally 

 with 3 S. The right leg two-jointed. 



From the above description of the female it is apparent that the only difference 

 between T. gracilis and T. forcijMtus consists (besides small differences in the length of 

 the joints of the first antennse) in the 5th p. of legs, being more asymmeti-ical in the latter 

 than in the former. It therefore seems to me questionable, whether they are to be con- 

 sidered as distinct species. 



