FISHERY BULLETIN: VOL. 82, NO. 4 



anterior 



epi branchials 



posterior 

 epibranchials 



coeli aco- 

 mesenteric artery 



dorsal left 

 gastric artery 



coeli aco-mesenteric 

 — shunt 



dorsal left gastric artery 



hepatic 

 branch 



coeliaco-mesen teric shunt 



9 



FIGURE 7. — Anterior arterial system in dorsal view of seven species of Scomberomorus . a. S. guttatus, Pakistan, 545 mm FL. b. S. 

 tritor, Gulf of Guinea, 494 mm FL. c. S. maculatus, Chesapeake Bay, 312 mm FL. d. S. concolor, Gulf of California, 455 mm FL. e. 

 S. sierra, Ecuador, 512 mm FL. f. S. brasiliensis, Belem market, Brazil, 588 mm FL, USNM 217557, paratype. g. S. regalis , Bahama 

 Is., 490 mm FL. 



olfactory rosette is located beneath the anterior 

 naris. Leaflike lamellae radiate from the central 

 axis and occupy the anterior dorsal third of the 

 olfactory cavity. Gooding (1963) studied the mor- 

 phology and histology of the olfactory organ of 

 Katsuwonus pelamis and found olfactory cells on 

 the olfactory epithelium of the lamellae. Iwai and 

 Nakamura (1964a) found that the number of 

 lamellae per rosette varies among specimens of 

 species of Thunnus but that there were differ- 

 ences among species in the shape of the nasal 



laminae. Most species of bonitos have 21-39 la- 

 mellae in each nasal rosette but Gymnosarda 

 unicolor is distinct in the group in having 48-56 

 (Collette and Chao 1975:532). 



The number of olfactory lamellae was counted 

 on both sides in Scomberomorus and a wide 

 range of variation was observed, 24-76 (Table 2). 

 In bonitos, the number of lamellae increases from 

 small specimens to adults but does not appear to 

 change after a certain size is reached, as Collette 

 and Chao (1975:532) showed for Gymnosarda 



558 



