44 
is equally obvious in the sole and the diodon. Of 
diodons, the most remarkable is distinguished by 
the agnomen, mola. “ It is,” says Dr. Shaw, “ of a 
silvery colour, with a cast of bluish brown; grows 
to a very large size, and perfectly represents the 
head of some very large fish, abruptly cut off from 
the body.” The long tails of lobsters and crayfish, 
which they employ with great activity in springing 
and swimming, are readily contrasted with the short, 
close, compressed tail of the crab: and if spiders be 
included amongst the crustacea, these may afford a 
no less striking contrast with the form of the scor- 
pion. It would be difficult to shew whether amongst 
insects the greater number belong to the short-tailed 
or to the long-tailed division. One of the bright 
blue libellule, or dragon flies, and a coccinella bi- 
punctata, called by children lady-cow, are on the 
same plant before my window. Not to mention the 
long hairs in the tails of ephemeree, in contrast with 
tailless tick. “ There is a tribe of minute insects 
amongst the aptera, found often under bark, some- 
times on the water, which Linnzeus has named po- 
dura, a term implying that they have a leg in the 
tail. This is literally the fact. For the tail, or 
anal extremity, of these insects is furnished with an 
inflexed fork, which, though usually bent under the 
body, they have the power of unbending; during 
which action the forked spring, pushing powerfully 
against the plane of position, enables the animal to 
leap two or three inches’.”. What is more remark- 
y A common child’s toy, sometimes formed to resemble a frog, 
