340 A DESCRIPTION OF 
the whole body is conical ; the colour of the back is deep 
blue, inclining to shining black ; the sides are grey, be- 
coming white below. The tail is forked, and composed of 
several rays united by a membrane. The body is covered 
with a rough skin, but has no scales : there are only three 
fins, one on the back, and one on each shoulder. The eyes 
are very small. When the flesh is cut up, it looks very 
much like pork ; but although it was once considered a 
sumptuous article of food, and is said to have been occa- 
sionally introduced at the tables of the old English nobility, 
it certainly has a disagreeable flavour. Porpoises live 
on small fish, and appear generally in large shoals in 
the mackerel and herring seasons, at which time they do 
very great damage to fishermen, by breaking and destroy- 
ing the nets to get at their prey. Their motion in the 
water is a kind of circular leap. They dive deep, but soon 
again rise up in order to breathe. They are so intent in 
the pursuit of their prey, that they sometimes ascend large 
rivers, and have even been seen above Westminster 
Bridge. They have no gills, and blow out the water with 
a loud noise, which in calm weather may be heard at a 
great distance. They are seen nearly in all seas, and are 
very common upon the British coasts, where they sport 
with great activity, chiefly at the approach of a squall. 
The Grampus, or Thresher, is a species of Porpoise, and 
a decided and inveterate enemy to the different species of 
whales ; which great flocks of them are said to attack, 
fastening round them like so many bull-dogs, making 
them roar out with pain, and frequently killing and de- 
vouring them. They are usually from twenty to twenty- 
five feet in length ; the general form and colour resemble 
the common Porpoise ; but the lower jaw is considerably 
wider than the upper, and the body, in proportion, is 
somewhat broader and more deep. The back-fin some- 
times measures six feet in length. In one of the poems 
of Waller, a story (founded on fact) is recorded of 
