PLAIN BONITO. 



163 



The second dorsal fin begins on a line rather before the anal 

 aperture, and has behind it eight finlets ; the anal fin com- 

 mences on a line with the hinder part of the second dorsal 

 fin, and has behind it seven finlets ; the tail is narrow, and 

 rather lunate in form, with a small lateral keel on each side. 

 The number of the fin-rays are, 



D. 10 12 VIII. : P. 21 : V. 1 + 5 : A. 12 VII. : C. 17, and 15 small. 



The back is irregularly mottled with two shades of indigo 

 blue ; the belly is silvery white ; the corselet rather darker 

 than the belly, or greyish white ; the fins darker grey, except 

 the anal fin, which is tinged with yellow. The lateral line 

 is not very strongly marked, and at the anterior part is lost 

 behind the corselet. The upper surface of the head is bluish 

 lead-colour ; the cheeks and gill-covers silvery. 



