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tional lengths of prosome and urosome about 

 77:23. Dorsally, forehead (Figure 4B) produced 

 as in A. acutiis. Rostrum reduced. Metasomal 

 process (Figures 4C, D) as in A. aciitiix. 

 Second to fourth urosomal segments and caudal 

 rami with width: length ratios of 1:0.93-0.95, 

 1:0.85-0.86. 1:0.88-0.89, and 1:2.27-2.38, re- 

 spectively. 



Antennules reaching about distal end of 

 third urosomal segment, nineteenth and long- 

 est segment (Figure 4F) with width: length 

 ratio of 1:3.75-3.86. Other cephalic appendages 

 as in A. acutus. On second leg (Figure 4H), 

 endopod extending beyond distal end of second 

 exopodal segment. Terminal expodal spine 

 longer than third exopodal segment, with about 

 24 teeth. Second to fourth segments of fifth 

 leg (Figure 41) with width: length ratios of 

 1:3.34-4.00, 1:6.00-6.25, and 1:5.00-6.65, re- 

 spectively. 



Rei)iark>i. — The male of A. giesbrechti is close 

 to A. niexiccuiKs in size but can be distin- 

 guished from it by the more produced forehead, 

 wide and curved metasomal process, relatively 

 short urosomal segments, wide nineteenth seg- 

 ment of the antennule, and long endopod of 

 the second leg. 



A. giesbrechti, including the male, was first 

 described with figures by Giesbrecht (1892) 

 under the name of A. armatus. Although the 

 female has been reported by many authors, the 

 male has since been found only by Bradford 

 (1971). The female specimens found in the' 

 present study (1.84-2.08 mm in body length 

 according to 76 randomly selected specimens) 

 are in agreement with the descriptions given 

 by Grice (1962) for the Pacific specimens. The 

 appendages are identical with those of A. acutus, 

 but the females of the two species are different 

 in the form of spermatheca (Figure 4A). 



Distribution. — As reviewed by Vervoort (1957). 

 A. giesbrechti has been found throughout the 

 world's oceans, except for the high latitudes. 

 In the Gulf of Mexico the species is quite com- 

 mon in the upper 500 m. 



LITERATURE CITED 



Bradford, J. M. 



1971. Aetideus and Euactidcus (Copepoda: Cala- 



noida) from the Atlantic and Pacific Oceans. 

 N. Z. J. Mar. Freshwater Res. 5: 12-40. 

 Brodsky. K. a. 



1962. On the fauna and distribution of Calanoida 

 in surface waters of the north-western Pacific [In 

 Russ.] Issled. Dal'nevost. Morei SSSR. 8:91-166. 

 De Decker, A., and F. J. Mombeck. 



1965. South African contribution to the Interna- 

 tional Indian Ocean Expedition: (4) A Preliminary 

 report on the planktonic Copepoda. S. Afr. Div. 

 Sea Fish. Invest. Rep. 51:10-67. 

 Farran, G. p. 



1929. Crustacea. Part X. Copepoda. Brit. Antarctic 

 (Terra Nova) Exped. 1910. Nat. Hist. Rep. Zool. 

 8(3):203-306. 



1936. Copepoda. Great Barrier Reef Exped. 1928- 

 29. Sci. Rep. 5(3): 73- 142. 

 Giesbrecht, W. 



1892. Sytemtik und Faunistik der pelagischen 

 Copepoden des Golfes von Neapel und der 

 angrenzenden Meeres-abschnitte. Fauna Flora Golf. 

 Neapel. Monogr. 19:1-830. 

 Grice, G. D. 



1962. Calanoid copepods from equatorial waters of 

 the Pacific Ocean. U.S. Fish Wildl. Serv., Fish. 

 Bull. 61:171-246. 



Grice, G. D., and K. Hulsemann. 



1965. Abundance, vertical distribution and tax- 

 onomy of calanoid copepods at selected stations 

 in the northeast Atlantic. J. Zool. 146:213-262. 

 1967. Bathypelagic calanoid copepods of the west- 

 ern Indian Ocean. Proc. U.S. Natl. Mus 122(3583): 

 1-67. 

 Owre, H. B., and M. Foyo. 



1967. Copepods of the Florida Current. Fauna Cari- 

 baea; Number 1. Crustacea, Part 1: Copepoda, 

 137 p. 



Park,T. 



1968. Calanoid copepods from the central North 

 Pacific Ocean. U.S. Fish Wildl. Serv., Fish. Bull. 

 66:527-572. 



1970. Calanoid copepods from the Caribbean Sea 

 and Gulf of Mexico. 2. New species and new rec- 

 ords from plankton samples. Bull. Mar. Sci. 

 20:472-546. 

 Sars, G. O. 



1924. Copepodes particulierement bathypelagiques 

 provenant des campagnes scientifiques du Prince 

 Albert F"" de Monaco. Result. Camp. Sci. Monaco 

 69, 408 p., 127 plates. 

 Tanaka, O. 



1957. The pelagic copepods of the Izu region, 

 Middle Japan. Systematic account III. Family 

 Aetideidae (Part 1). Publ. Seto Mar. Biol. Lab. 

 6:31-68. 

 Tanaka. O., and M. Omori. 



1970. Additional report on calanoid copepods from 

 the Izu region. Part 3-A. Eiiaetideiis, Aetideopsis, 

 CInridius, Gaidnis, and Gaetanus. Publ. Seto Mar. 

 Biol. Lab. 18:109-141. 

 Vervoort, W. 



1957. Copepods from Antarctic and sub-Antarctic 

 plankton samples. B.A.N.Z. Antarctic Res. Exped. 

 1929-1931. Rep., Ser. B (Zool. Bot.) 3, 160 p. 



221 



