84 THE COMMERCIAL SEA FISHES OF 



does not reach to the iris, and is attached by its lower edge 

 to the suborbitals ; diameter of the eye i to \ in the length 

 of the head, i-^- diameters apart. The length of the snout is 

 equal to about \ of that of the entire head. The maxilla 

 reaches to beneath the middle of the orbit. Teeth. In a 

 single row in the jaws, in a deciduous patch on either side 

 of the vomer, and in a single or double row on the palatines ; 

 a row likewise at the centre of the base of the tongue. 

 Fins. Dorsal spines weak, the second and third the 

 longest. Scales. Minute, about twenty-one rows between 

 the base of the first dorsal fin and the lateral-line ; along 

 the sides and lower surface of the abdomen they become 

 almost indistinguishable. A keel along either side of the 

 root of each lobe of the caudal fin. Air-bladder. Absent. 

 Ccecal appendages. Numerous. Colours. Upper third of 

 the body green, shot with blue ; while the sides and 

 abdomen are glossed with gold, silver, and purple shades. 

 About thirty-five V-shaped bands pass downwards from the 

 back terminating on or below the lateral-line ; a dark 

 stripe, sometimes interrupted, passes from the base of the 

 pectoral-fin along the side, a short distance below the 

 lateral-line. Fins dark. 



Varieties. The British forms of mackerel have been 

 divided into the commercial species which possesses no air- 

 bladder, and a rare form known as the Spanish mackerel 

 (Scomber colias\ which is furnished with one ; it has likewise 

 large scales over the region of the breast, and a larger eye. 

 Our commercial form shows great varieties in colour, more 

 especially among those captured along our south and 

 south-west coasts. There is one form in which there are 

 no markings visible along the upper half of the body, or the 

 unmarked mackerel ; there is another in which the upper 

 two-thirds of the body appears as if scribbled over with 



