COPEPODA. 265 



The 4th joint terminates with a long filament. The inner 

 20. 21. 12. 8. 6. 6. 3. 5. ,J & 



branch of posterior antennas is 2-jointed, the 2nd joint being very small. 



Mouth organs and 2nd, 3rd, and 4th pairs of natatory legs as in A. minor. First 

 joint of inner branch of 1st pair of legs as long as entire 3-jointed outer branch ; 3rd 

 inner joint long and narrow. 



Basal joint of 5th pair of legs triangular, bearing 2 short plumose setas and 3 plain 

 ones. Outer joint long and narrow, 4 times as long as broad ; fringed on both sides 

 with fine hairs, and having 4 terminal setas and 1 lateral. 



One specimen only, a female, was found in the Muttuvaratu pearl oyster washings. 

 Although the inner branch of the posterior antennas is 2-jointed, we have thought it 

 best to include this species in the genus Ameira, with which it agrees in all other 

 particulars. The 1st and 5th natatory legs readily distinguish it from other species. 



Ceylonia, n. gen. 



Cephalothorax and abdomen each 5-jointed. Anterior antennas 7 -jointed. Inner 

 branch of posterior antennas 1 -jointed. Mandible palp with one small branch. Second 

 maxilliped non-prehensile. Inner branches of 1st to 4th pairs of natatory legs all 

 2-jointed ; outer branches 3-jointed ; 5th pair foliaceous. 



The genus Ceylonia is nearly related to Mesochra, and might have been incor- 

 porated therewith but for the structural difference in the 1st pair of natatory legs 

 and in the maxillipeds. 



Ceylonia aculeata, n. sp. Plate VII., figs. 11 to 23. 



Length, female 1"2 millim ; male 1 millim. 



Body robust throughout; cephalothorax and abdomen each 5-jointed, the first two 

 abdominal joints imperfectly divided. Rostrum short and blunt. 



Anterior antennas short and stout, thickly setiferous, 7 -jointed, a long thick filament 

 protruding from the apex of 4th joint. The proportional lengths of the joints are as 



1. 2. 3. 4. 5. 6. 7 . 

 folWs : 16. 12. 16. 9. 3. 6. 11. 



Outer branch of posterior antennas 2-jointed, the outer edge and apex of 2nd joint 

 lined with 6 stout spines ; inner branch composed of one joint with 2 ajiical spines. 



Biting part of mandible consists of 3 large teeth ; palp with small branch, spinous 

 at apex. First maxilliped has terminal claw and two 1 -jointed branches with apical 

 plumose setas. Second maxilliped wedge-shaped, non-prehensile, but with small 

 curved rudimentary claw. 



Inner branches of 1st to 4th natatory legs 2-jointed; outer branches 3-jointed. 

 Inner branches of 1st pair only the length of outer branch, both bearing strong 

 spines ; a remarkable rod-like projection with hirsute termination extends from the 

 centre of 1st joint of inner branch. The middle joint of outer branch of male 



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