Zoology.-] NATUEAL HISTORY OF VICTORIA. [Fishes. 



Plate 44, Fig. 2, 



THYNNUS THYNNUS (Lin. sp.). 

 The Tunny. 



[Genus THYNNUS (Cuv.). Sub-kingd. Vertebrata. Class Pisces. Sub-Class Teleostea. 

 Order Acanthopterygia. Earn. Scomberidse). 



Gen. Char. — Body thick, fusiform, tapering each way from about pectoral \ 1st dorsal fin 

 moderate, of rather small spines, reaching nearly or quite to 2nd dorsal ; 6 to 9 finlets behind 

 the dorsal and anal fins. Scales of the pectoral region larger than the others, forming a corslet. 

 Jaws moderate with small teeth, and still smaller on the vomer and palatine bones. A loDgitu- 

 dinal keel on middle of each side of the tail. Air-bladder simple or absent. Pyloric appendages 

 numerous. Branchiostegal rays, 7. Open sea of tropical and temperate regions.] 



Description. — Fin-rays : 1st dorsal of 13 to 15 spines, 1st longest; 2nd 

 dorsal of 13 to 15 spines ; 8 or 9 pinnule above and below ; anal, 12 to 14 ; ventral, 

 6 to 7 ; pectoral, 30 to 34; caudal, about 18 rays above and below, with about 9 or 

 10 smaller ones in the middle. Form : Height of body and length of head almost 

 equal, and less than 3^ in total length to middle of posterior edge of caudal fin ; 

 pectoral reaching to vertical from 11th dorsal spine; body thick, fusiform, broad, 

 ovate ; greatest depth of body and length of head nearly equal ; lower jaw slightly 

 longer than the upper. Teeth : 30 to 36 teeth on edge of lower jaw, those on upper 

 jaw smaller and more numerous ; a band of 4 rows of very minute teeth on the 

 palatine bone of each side; midline of vomer with still more minute teeth in many 

 rows, forming a small, dilated, triangular patch in front. Scales : The large scales 

 forming the corslet are not very distinctly distinguishable until the skin is dry; 

 they occupy a space, the posterior boundary of which varies, but generally extending 

 in a narrow strip backward along base of the dorsal fins, descending about opposite 

 the middle of 1st dorsal, and then running back at an acute angle as far as the 

 end of the 2nd dorsal, thence forward to below base of pectoral, which can be 

 sunk in a depression fitting it. The scales of lateral line distinct from middle 

 anole of corslet to ridge on side of tail, of larger and stronger scales than the body 

 behind the corslet, each rotundato-quadrate, and with a prominent tubular keel ; the 

 line is slightly flexuous. Preoperculum with irregular longitudinal short grooves. 

 Color: uniform purplish-black, with steel-blue reflections above; with brownish 

 tinges on the top and sides of the head; belly and lower part of the sides silvery- 

 white ; fins dark brownish-purple, except the pectoral, which is black ; finlets rich 

 chrome-yellow, with a narrow, blackish margin ; tongue and mouth black ; iris 

 golden-yellow on the outer margin, greenish and silvery towards inner edge. 



Reference. = Scomber thynnus. Lin., Syst. Nat., p. 493; = Thynnxis vul- 

 garis, Cuv. and Val., Hist. Pois., vol. 8, t. 210. Couch, Fish Brit. Is., vol. 2, 

 p. 86, t. 82; = T. Maccoyi (Cast.), Proc. Zool. & Ac. Soc. Vict., v. 1, p. 104. 



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