160 THE MACKEREL FAMILY. 



Trachinus should have so many features in common in regard 

 to the armature of the head and the general shape. 



Couch' describes a young example of what he considers to 

 be the greater weever, measuring only | of an inch in length 

 and captured with a drift-net in August. The opercular spine 

 was not much developed, and the same may be said of those at 

 the anterior superior angles of the orbit. Pigment occurred on 

 the head and anterior portions of the body, diminishing towards 

 the posterior region — which was translucent. " The lower part 

 of the pectoral fins have colour, but the upper portion is devoid 

 of it. Two or three rays on the inner portion of the ventral 

 fins are black." 



The Mackerel Family. Scombridae. 



The Mackerel. {Scomber scombrus, L.) 



The mackerel forms an instance of a fish, whose pelagic 

 habits are not, as in the case of the haddock or the cod, confined 

 to the embryonic and larval stages, but the surface-water in the 

 open seas is the haunt of this species throughout life, with 

 perhaps the exception of its verj' young stages. This exception 

 is fraught with interest to the investigator, for it might with 

 some reason be conjectured that a fish living in mid-ocean and 

 having a floating egg would thereby be enabled to spend the 

 whole of its life without approaching the proximity of land, in 

 which case it would not be to any great extent available as food 

 for man. Fortunately this is not the case, for the mackerel 

 congregates in vast shoals, and these leaving the open sea 

 migrate towards the land and discharge their eggs in the 

 inshore waters. The periodic migrations of myriads of fishes, as 

 occurs in the case of the mackerel and the herring, are not by 

 any means well understood, but the tendency amongst naturalists 

 is to regard them as migrations connected with the discharge of 

 the sexual function : thus some may be inclined to hold that 

 the mackerel has become secondarily adapted to a pelagic life 



I Vol. II. p. 4(;, 



