and painstaking anatomical descriptions are found 

 in his works and those of Godsil and Byers (1944) 

 and Godsil and HolmberK (1950). 



This paper is divided into two major sections. 

 The first ])art describes and compares the osteology, 

 viscera, vascular system, meristic characters, mor- 

 phometry, and coloration among the species. The 

 second part considers the systematic position of the 

 genus Thunniis. Each species is treated separately, 

 including a synonymy, diagnosis (based on char- 

 acters from the first section), discussion of nominal 

 species, and outline of geographical distribution. 



MATERIALS AND ACKNOWLEDGMENTS 



We have examined, measured, and made counts 

 on numerous specimens of all Western Atlantic 

 species. Alany specimens taken in pound nets in 

 Cape Cod Bay were made available through the 

 courtesy of .John E. Vetorino, Mike Goulart, and 

 Adam Rupkus. Most material for di.ssection and a 

 large share of the total specimens examined were 

 collected on exploratory longline cruises, by the 

 Bureau of Commercial Fisheries vessels Delaware in 

 the Gulf Stream and adjacent waters east to the 

 Azores and Oregon in the Gulf of Mexico and Carib- 

 bean Sea. For saving valual)le specimens and for 

 allowing us to participate in many cruises, we are 

 particularly indebted to Harvey R. Bullis, Peter C. 

 Wilson, and ,James L. Squire. The late Al Pflueger 

 of Miami, Fla., and Frank .J. Mather III of Woods 

 Hole Oceanographic Institution (WHOI), gave us a 

 number of specimens. Ivhvard C. Raney lent us 

 skeletons from Cornell University. Margaret E. 

 Watson of WHOI and Donald P. de Sylva of the 

 University of Miami Institute of ^Marine Science 

 allowed us to examine other specimens. 



Soutlieast Pacific specimens of T. ohesiis and T. 

 albaearrs were dissected (hu'ing our participation in 

 cruise 14 of the Anton Bruun, part of the South East 

 Pacific Biological Oceanographic Program sponsored 

 by the National Science Foundation. Australian 

 and Japanese tunas were examined in the fish mar- 

 kets of Tokyo and Yaizu. We obtained whole speci- 

 mens or skeletal material of Pacific species from the 

 Inter-American Tropical Tuna Commission (M. B. 

 Schaefer and Craig Orange); California State Fish- 

 eries Laboratory (Phil Roedel and Harold B. 

 Clemens) ; Bureau of Commercial Fi-sheries Biological 

 Laboratory, Honolulu (.John C. Marr); Nankai 

 Regional I'isheries Laboratory, Kochi, Japan (Hir- 



oshi Nakamura and Shoji Ueyanagi); Tokyo Uni- 

 versity (Tokiharu Abe); Kyoto University, Maizuru, 

 Japan (Izumi Nakamura and Tamotau Iwai); 

 Institut Fran^ais d'Oceanie, Notmiea, New Cale- 

 donia (Michel Legand); and C.S.I.R.O. Marine 

 Laboratory, Cronulla, Australia (J. C. Moore and 

 J. P. Robins). 



Specimens from the Indian Oe'can were received 

 from the Nankai Laboratory and from crui.ses of the 

 Anton Bruun made during the U.S. Program in 

 Biology of the International Indian Ocean Expedi- 

 tion. Frank II. Talbot and Michael Penrith pro- 

 vided South African specimens and skeletons. 



We examined specimens and .skeletons of botii 

 Atlantic and Pacific forms at the California Academy 

 of Sciences (W. I. Follett); Stanford University 

 (George S. Myers and Warren C. Freihofer); Uni- 

 versity of California at Los Angeles (Wayne .1. 

 Baldwin); Scripps Institution of Oceanography 

 (Richard H. Rosenblatt); and the U.S. National 

 Museum and skeletons of Pacific and Indian Ocean 

 specimens at Kyoto University, Maizuru (Tamotsu 

 Iwai and Izumi Nakamura) and the Nankai labora- 

 tory (Shoji IVyanagi). 



All available types were examined at the Museum 

 National d'Histoire Naturelle (MXHN), Paris 

 (M. L. Bauchot and C. Roux) ; at the Rijksmuseum 

 van Natuurlijke HLstorie (RMNH), Leiden (M. 

 Boeseman) ; and at the Academy of Natural Sciences, 

 Philadelphia (ANSP) (James E. Bohlke). We re- 

 ceived information on tyi)es in the Australian Mu- 

 seum in Sydney and the Dominion Museum in 

 Wellington from Frank H. Talbot and J. Moreland, 

 respectively. 



We made thorough examinations of viscera and 

 blood vessels on the following (sizes in mm.): 



Thnninis iihilunga <• .\tl;i!ilic (7S0- l,2.')0i, 1 I'acific 



(992), 2 Indian (ca. 9(K)-970) 

 Thnnnus albacares 15 .-Vtlantic (600-1,515), 4 Pacific 



(070-941), 11 Indian (001-895) 

 Thunmis allaiUicus 21 (322-065) 

 Thurnius ohexiis 17 Atlantic (697-1,545), 5 Pacific (851- 



1,614), 2 Indian (630-680) 

 Thuntius maccoyii '.i (742-1,442) 

 Thunnus thynniii! Ihyntnis 10 (310-2,315') 

 ThutDitis thynmis oriental in 3 (014-1, (."(O) 

 Tfinunus tonggol 4 (37:5-924) 



The following complete skeletons (most of which 

 arc now in the U.S. National Museum) provide the 

 basis for our analysis. These include a large share 

 of the material of Godsil and Byers (1944) and Godsil 



66 



U.S. FISH AND WILDLIFE SERVICE 



