iQiS.] R. B. S. SeweIvL : New species of Copepoda. 9 



segment is claw-like and is serrated on its margin. The left leg : 

 basal I is produced in a long claw-like process, terminating in a 

 point ; exopod i bears a distal marginal spine ; exopod 2 and 3 

 forms a flattened leaf-like plate, broader than in P. lobipes and on 

 the outer margin is a short sharp spine serrated on both borders ; 

 the inner margin of the plate is smooth. 



Family PONTELLIDAK. 



Genus Acartia, Dana. 



Acartia chilkacnsis, sp. nov. 



(Plate IX, figs. 1-5.) 



Examples of both sexes were present in the Chilka Lake 

 collection. 



5 . Total length ^ 075 mm. 



Proportional length of cephalo-thorax and abdomen — 

 74 : 26 = 100. 



The head and ist thoracic segment are separate ; thoracic 

 segments 4 and 5 are fused. The posterior thoracic margin is 

 rounded and is armed with a series of small spines. 



The abdomen consists of three segments; of these the ist and 

 2nd are armed on the dorsal part of the posterior margin with 

 a row of minute spinules. The furcal rami are symmetrical ; 

 the 2nd furcal seta is much longer but not any stouter than 

 the rest ; the 5th seta arises about half-way along the outer margin 

 of the ramus. 



The abdominal segments and furca have the following propor- 

 tional lengths : — 



39 : 19 : 17 : 25 =^ 100. 



The 1st antennae when folded back reach to the middle of the 

 ist abdominal segment. The segments have the following propor- 

 tional lengths : — 



Segments 1:2-6:7: 8-10 : n : 12 : 13 : 14 : 15 : i6 : 17 : i8 : 19 : 20 : 21 : 

 51 : 95 : 15 : 51 : 29 : 36 : 29 : 58 : 58 : 36 : 55 : 70 : 58 : 51 : 66 : 

 22 : 23 : 24 : 25. 



48 : 66 : 44 : 29 = 1000. 



Segments i6, 17 and 19 are all armed with a transverse row of 

 minute spines on the distal part of the posterior margin. There 

 are no spines on any of the basal segments. 



The $th pair of legs. — These closely resemble those of A. 

 centrura ; the basal segment bears a long marginal seta, and the 

 distal portion is dilated basally and is then produced in a curved 

 spinous process with a small notch in the outer margin about the 

 middle of its length. 



(f . Total length = 0*70 mm. 



Proportional length of cephalo-thorax and abdomen — 

 75 : 25 = 100. 



