SURFACE COPEPODA OF THE GULF OF MANNAR. 191 



NOTES ON THE SURFACE COPEPODA OF THE 

 GULF OF MANNAR. 



By Captain R. B. Seymour Sewell, B.A., I.M.S. 



Surgeon-Naturalist to the Marine Survey of India and Honorary 



Assistant Superintendent, Zoological and Anthropological 



Section, Indian Museum, Calcutta. 



(With five Plates and one Map.) 



rT"^HE collections on which the following notes are based are 

 ._!_ two in number. The first of these is a very extensive 

 one from the Ceylon pearl banks and neighbouring waters. 

 This collection was made by Mr. T. Southwell during the 

 years 1906-09, when he was Scientific Adviser to the Ceylon 

 Pearl Fishery Syndicate, and comprises 326 samples ; at the 

 time when the Syndicate ceased its operations, this collection 

 was handed over to Dr. J. Pearson, the Director of the 

 Colombo Museum, and I have to thank him for entrusting it 

 to me for examination. The second collection was made by 

 Mr. S. W, Kemp, of the Indian Museum, during the month of 

 February, 1913, at Paumben and Kilakarai on the south 

 coast of India. The collections proved to be exceedingly rich, 

 containing in all 87 species and varieties, of which five are 

 noAv to science, namely, Acrocalanus similis, Scolecithricella 

 pearsoni, Centropages trispinosus, Acartia southwelli, Acartiella 

 kempi, gen, nov. ; and in addition I am able to record the 

 occurrence of the following hitherto unknown forms : — 

 Eucalanus mucronatus, S ', Labidocera pavo, $ ; Acartia 

 amboinensis, ? ; Tortanus jorcipatus, $. 



In the accompanying table I have given a complete list of 

 the various species and varieties, and have indicated by -f 

 the various localities in which they were present. For the 

 most part the species are widely distributed, but it is of 

 interest to note that the species of the genera Euchgeta, 

 Scolecithrix, Scolecithricella, and Candacia appear to be very 

 largely confined to the region of the pearl banks lying to the 

 west of Karativu island, between it and the overfalls, includuig 



