5 
The mackerel is the head, or typical fish, but one of the 
smallest in size, of a large family, which has representatives 
in every sea in the world, except in the regions of extreme 
cold, and every member of which is excellent as food. 
The first distinguishing mark of the family to an outside 
observer is a tail having a peculiar fork. You can see it in 
a moment in the fish market here. The next is the 
cleanness of the lines on which the fish is built. The long 
conical forepart of the body and snout, the smooth round 
body, and the clean run of the afterpart, all fit the fish for 
rapid propulsion through the water, whilst the powerful 
forked tail, working with much less opposition to the water 
than would a rounded tail, and precisely with the action 
with which the sailor sculls his boat by one oar over the 
stern, enables the fish to make the greatest possible use of 
the advantages of its shape. The last distinguishing exterior 
feature which I shall notice is the existence between the 
base of the tail fin, and the hindmost upper and under fins, 
and both above and below the body, of a series of little 
soft rudimentary fins, called finlets, and the use of which is 
obscure. This family includes the bonitos, the tunnies, the 
albacores, and other Mediterranean fish, all occasional 
visitants of our Western seas, and just excludes (if, indeed, 
it does exclude, for I, who have seen the fish, am not clear 
about it,) the Northern “ opah,” a noble great fellow, some 
four to five feet long, which would more than cover an 
ordinary card-table, and is a very Assyrian for “ gleaming 
in purple and gold,” being in fact almost the only northern 
fish which excels in splendour of colour the fish of the seas 
of the temperate zones and the tropics. I do not at this 
moment recollect whether there is a specimen of this fish 
in the building. If there is, you will find it in the court of 
Norway or possibly of Denmark. 
