COPEPODA FROM IFALUK ATOLL 7 



Order Calanoida 



Family Centropagidae Giesbrecht, 1892 



Genus Centropages Kr0yer, 1849 



Centropages orsinii Giesbrecht, 1889 



Figure la 



Centropages orsinii Giesbrecht, 1889, p. 811; 1892, pp. 305, 316, 321, pi. 17 (figs. 

 35, 36, 41, 42), pi. 18 (figs. 2, 14, 23), pi. 38 (figs. 12, 19); 1896, pp. 317, 

 318, 319.— Giesbrecht and Schmeil, 1898, p. 57.— Cleve, 1900b, p. 1026; 

 1901, p. 5.— A. Scott, 1902, pp. 404, 423.— Thompson and Scott, 1903, p. 

 247.— Cleve, 1904, p. 359.— Wolfenden, 1905, p. 1015, pi. 98 (figs. 1, 4, 5, 

 8, 11, 12).— A. Scott, 1909, p. 115.— SeweU, 1912, pp. 315, 362.— Brady, 

 1915, p. 135.— Fruchtl, 1923, p. 450; 1924, p. 44.— Rose, 1924a, p. 485.— 

 Menon, 1931, p. 509.— SeweU, 1932, p. 230.— Dakin and Colefax, 1933, 

 p. 205.— Farran, 1936, p. 109.— Mori, 1937, p. 60, pi. 29 (figs. 1-7).— Dakin 

 and Colefax, 1940, p. 91, figs. llOa-c— Mori, 1942, pp. 553, 569.— Tokioka, 

 1942, p. 181.— Sewell, 1947, p. 163.— C. B. Wilson, 1950, p. 187.— Krish- 

 naswamy, 1953, p. 122.— Tanaka, 1953, p. 133.— Rose, 1955, p. 391.— Chiba, 

 1956, p. 41.— Rose, 1956, p. 460. 



Material. — Loc. 194-E-5, 1 ad. cf, 1.11 mm. 



Remarks. — One male specimen of this form occurred in a sm-face 

 haul made in the open lagoon. Centropages orsinii is a species which 

 is distributed widely in the tropical parts of the Indian and Pacific 

 oceans: Durban Bay, Union of South Africa (Brady, 1915); the 

 Gulf of Aden (A. Scott, 1902; Cleve, 1904); the Red Sea (Giesbrecht, 

 1889, 1892; Cleve, 1900b, 1904); the Arabian Sea, including the 

 Maldive and Laccadive Islands (Cleve, 1900b, 1904; Wolfenden, 

 1905; Sewell, 1912); the Persian Gulf (Pesta, 1913); the Bay of 

 Bengal, including the Gulf of Mannar and the Ceylon pearl oyster 

 banks, and Madras (Thompson and A. Scott, 1903; Sewell, 1912, 

 1932; Menon, 1931; Krishnaswamy, 1953); the Malay Archipelago 

 (Cleve, 1901; A. Scott, 1909; Fruchtl, 1924); the Great Barrier Reef 

 of Australia (Farran, 1936); the coastal waters of New South Wales, 

 Australia (Dakin and Colefax, 1933, 1940); the Fiji Islands (C. B. 

 Wilson, 1950); the Palau Islands, Marshall Islands (Mori, 1942; 

 C. B. Wilson, 1950); and the coastal waters of Japan (Tanaka, 

 1953). Farran's specimens from the Great Barrier Reef are of par- 

 ticular importance; the females measured 1.20-1.56 mm., the males 

 1.20-1.38 mm. There appeared to be a considerable variability in 

 length in both sexes. The species occurred both inside and outside 

 the reef. The Ifaluk specimen is slightly smaller than the minimal 

 length given by Farran, but its occurrence fits well into the normal 

 area of distribution. 



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