106 
ANIMAL CURIOSITIES 
sideways gait, yet those known as swimming 
crabs, of which several species are to be found 
around our coasts, possess specially developed 
legs, the last pair being flattened, and ter¬ 
minating in oval, plate-like structures that 
serve as oars and enable the creatures to make 
their way through the water in any direction. 
One of the better-known kinds is the velvet 
swimming-crab, so called on account of the 
thick covering of short hairs upon the upper 
part of its shell. It is a handsome species, 
the general greyish tint of its shell being 
relieved by a violet-coloured border, while 
the feet, more especially the flattened plates, 
are barred with black stripes. The fore claws 
are decorated with scarlet and azure tints, 
and the eyes are vermilion in colour. 
A curious group of crabs are those known 
as spider-crabs because of the triangular form 
of their bodies—the carapace being broad at 
the back and narrow in front. In some kinds, 
moreover, the limbs are of such extreme 
length and slenderness as to resemble those of 
a spider. Of the various species found in 
British seas the spinous spider-crab or thorn- 
back crab is one of the most familiar. It attains 
to a considerable size, a specimen taken in 
Liverpool Sound having measured eight inches 
in length and six inches in breadth. 
