SURFACE COPEPODA OF THE GULF OF MANNAR. 213 



First Antenna. — As in other members of this genus, the 

 basal segments are fused together to form two large joints. 

 The proportional lengths of the various joints are as follows : — 



Segments: 1-6. 7-8. 9. 10. 11. 12. 13. 14. 15. 16. 

 286 73 24 25 29 29 .36 34 39 39 



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

 39 41 44 44 48 48 48 44 29 



Second Antenna. — As in other members of the genus, in 

 adult males the last joint of the exopodite is devoid of setaj, 

 and forms a nipple like projection. 



The first to fourth pairs of swimming feet are the same as 

 in the female ; the fifth leg on the left side is present, and 

 consists of a somewhat swollen basal segment and four free 

 joints : the terminal joint bears two unequal setae, and the 

 penultimate joint has a short spine at its distal external angle. 



It is obvious that this species is very closely related to 

 A. inermis, from the Burma coast, but it differs from it in the 

 following characters : — 



(1) The total length is somewhat smaller. 



(2) The terminal segment of the first antenna in the 



female is somewhat longer, and there are no 

 transverse rows of spinules on segments 1-6. 



(3) There are no spinules on the posterior thoracic margin. 



(4) There are no spines on the posterior aspect of exopod 2 



of any of the swimming legs. 



(5) The rostrum is long and slender. 



It is possible that these differences may be merely due to 

 altered environment, but for the present I prefer to consider 

 the above a new species, and I have therefore given it the 

 name A. similis. 



Genus CalGCalanus, Giesbrecht. 

 Calocalanu? pavo (Dana). 



Calocalanus faro, Giesbrecht, 1896, p. 317. 



Thompson, 1899, p. 277. 



Cleve, 1901, p. 5. 



2v 6(10)13 



