FISHERY BULLETIN: VOL. 73, NO. 3 



tendency supports the findings of Godsil (1955). 

 However, a seventh southeast Pacific specimen 

 had a considerably longer caecal mass (70%) than 

 our other six specimens. 



The position and size of the spleen are distinc- 

 tive among the genera. Species of Sarda have a 

 large spleen, the major portion of which is located 

 in the posterior half of the body cavity between 

 the intestine and the stomach in ventral view. The 

 spleen of Gymnosarda is also visible ventrally, but 

 it is smaller than in Sarda and located in the 

 anterior half of the body cavity. In Orcynopsis and 

 Cybiosarda, the spleen is hidden by the right lobe 

 of the liver and caecal mass. The spleen was visible 

 in ventral view in one specimen of the four 

 Allothunnus examined. 



The number of loops in the intestine separates 

 Sarda and Allothunnus from the other three 

 genera of bonitos. In Sarda and Allothunnus, the 

 intestine leaves the stomach and then moves 

 posteriorly along the right side of the body cavity 

 straight to the anus (Figure 5a). In the other 

 genera, the intestine makes a loop at about the 

 level of the posterior end of the stomach, runs 



CAECAL MASS DUCTS 



SMALL INTESTINE 



STOMACH 



a 



LARGE INTESTINE 



ANUS 



Figure S.-Course of intestine from stomach, through area 

 where the ducts of the caecal mass empty into the intestine, to 

 the anus in two species of Sardini, ventral view (diagrammatic), 

 a. Sarda orientalis, Tokyo, 341 mm FL. b. Cybiosarda elegans, 

 New South Wales, 365 mm FL. 



anteriorly almost to where it came off the 

 stomach, forms another loop, and then goes 

 straight posteriorly to the anus (Figure 5b). 



The caecal mass is connected to the anterior part 

 of the intestine by 6-9 ducts as shown diagram- 

 matically in Figure 5. Each of the main ducts 

 branches into numerous smaller ducts within a 

 short distance from the intestine. We did not 

 count the number of ducts often enough to deter- 

 mine the systematic value of this character and so 

 merely present the results for six specimens: 

 Cybiosarda-S anterior and 5 posterior ducts in one 

 specimen, 3 anterior and 6 posterior in another; 

 Sarda australis—3 anterior and 4 posterior; S. 

 chiliensis—2 anterior and 4 posterior; S. orien- 

 talis— S anterior and 4 posterior; and Gymnosar- 

 da— a. total of 6 ducts. 



VASCULAR SYSTEM 



The only published work on the vascular system 

 of the bonitos is on the Pacific species Sarda 

 orientalis by Kishinouye (1923) and Godsil (1954, 

 1955) and on S. chiliensis by Godsil (1954, 1955). No 

 specialized subcutaneous vascular system and no 

 cutaneous arteries or veins are present as they are 

 in the higher tunas, Auxis to Thunnus. Therefore, 

 this description will be confined to the anterior 

 portion of the dorsal aorta and the postcardinal 

 vein. 



General Description.— The efferent branchial 

 (epibranchial) arteries and coeliaco-mesenteric 

 artery form a unit at the anterior end of the dorsal 

 aorta (Figure 6). Two anterior epibranchials on 

 each side unite to form a common trunk, and these 

 trunks join as the "Y" of the aorta beneath the 

 first or second vertebra. The posterior two 

 epibranchials of each side unite immediately 

 before they join the aorta, usually ventral to the 

 second or third vertebra. As the aorta proceeds 

 posteriorly it gives rise to the large coeliaco- 

 mesenteric artery on the right side ventral to the 

 second to fourth vertebra. The coeliaco-mesenteric 



Figure 6.— Anterior part of arterial system in seven species of 

 Sardini. Numbers indicate vertebral centra; stippled areas show 

 where pharyngeal muscles originate, a. Cybiosarda elegans, 

 Western Australia, 422 mm FL. b. Orcynopsis unicolor, Tunisia, 

 543 mm FL. c. Sarda australis, New South Wales, 408 mm FL. d. 

 Sarda orientalis, Tokyo, 500 mm FL. e. Sarda sarda, eastern 

 United States, 388 mm FL. f. Gymnosarda unicolor, Truk 

 Islands, 772 mm FL. g. Allothunnus fallai, Tasmania, 764 mm 

 FL. 



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