SURFACE COPEPODA OF THE GULF OF MANNAR. 201 



EucALANUS MUCRONATUS, Giesbrecht. 



Euccdanus mucronalus, Cleve, 1901, p. 7. 



Cleve, 1903, p. 362. 



Cleve, 1904, p. 189. 



Wolfenden, 1905, p. 996. 



Scott, 1909, p. 20. 



Several examples of this species were obtained, although it 

 was by no means common. Hitherto only the female form 

 has been known, but in a tow-netting from Dutch Moderagam 

 Paar, associated with several females was a single male 

 specimen, that shows the following characters : — 



(J. Total length, 3 ' 3 mm. 



The proportions of the cephalothorax and abdomen are as 

 7:1. The head and first thoracic segments are fused, but 

 the fourth and fifth thoracic segments are separate. The 

 anterior extremity of the head region is produced in a spike, 

 as in the female. 



The abdomen consists of four segments, of which the second 

 and third are slightly longer than the first, and the anal 

 segment is quite short. The f ureal setae are asymmetrical, 

 the second seta on the left side being much longer and stouter 

 than the others. 



The first antennse are long, over -reaching the tip of the 

 furcal rami by the last five or six segments. The proportional 

 lengths of the various segments are as follows, and for 

 purposes of comparison I give the lengths of the segments 

 in the female : — 



Segments : 1-2. 3. 4. 5. . 6. 7. 8-9. 10. 11. 12. 13. 

 9. .. 123 25 25 25 25 29 50 34 34 39 43 

 cJ. . . 69 69 24 24 24 24 26 52 38 38 48 52 



Segments : 14. 15. 16. 17. 18. 19. 20. 21. 22. 23. 24. 25. 

 $. ..45 49 49 49 53 53 49 49 41 41 29 41 

 (J. . . 52 53 52 52 48 48 41 41 32 38 27 38 



In the main the proportions of the joints are very much the 

 same, the prmcipal differences being the fusion of segments 1 

 and 2 in the female, and the short 22nd segment in the male. 



