QUEER CHIMNEY BUILDERS 197 
happiness, and by retiring from the field during 
daylight hours does his best to live peaceably 
among his neighbors. 
“ Crawfish towns are scattered pretty well over 
the world. But there is one thing on which the 
crawfish insists: he must live near fresh water. 
He has a big overgrown cousin, however, the lob¬ 
ster, a scavenger lover like himself, who prefers 
the salt water, and judging from his size, he cer¬ 
tainly thrives well in it. There is but one slight 
difference in the general make-up of the craw¬ 
fish and the lobster. That difference is in the 
tail. Both the crawfish and the lobster have fin- 
like tails. The lobster’s is composed of three 
round plates; while in the crawfish there is a di¬ 
vision in the second and third plates making five 
in all. Otherwise the difference in the two cousins 
is practically one of size and environment. 
“ The limy external skeleton of the crawfish 
resembles a crust, and as he is a typical specimen 
of a host of kindred, the name Crustacean is ap¬ 
plied to the whole order. Other well-known 
cousins are the crabs, barnacles, sow bugs, and 
water fleas. All the crustaceans are remarkable 
for the ease with which they adapt themselves to 
various and widely different conditions of life. 
We find them living in fresh water, in the sea, on 
land, and as parasites. In Mammoth Cave is a 
species of blind crawfish which shows plainly that 
