Tv. AND REVIVED. 173 
called progreflive motion, which conftitutes a 
difference between them and the other refurgent 
animals. ‘They never rife in the water, nor do 
they crawl on the fides of the veflel ; they con- 
ftantly remain at the bottom, appearing like a pel- 
licle or fpot darker or lighter according as they 
are more or lefs numerous. 
If the water fails, whether by evaporation or 
otherwife, the eels gradually become lifelefs, and 
motion ceafes when there is no more water. The 
other three kinds of refurgent animals have the 
prudence to fly the places where the water dries ; 
but the eels continue in the fame fpot without at- 
tempting to efcape. 
In feveral hours, they become very dry, and 
adhere to the fubftances below fo tenacioully, 
that it is difficult to feparate them without break- 
ing: when wet, they feparate eafily, efpecially 
with the point of a needle. They foon foften, 
and, becoming pliant, it is evident they are of a 
gelatinous confiftence: and an iron inftrument 
cannot touch them without injury. This, at 
leaft, happens while alive : when dead fome days, 
they are {till very fragile, yet have more cohe- 
fion than one would think : they refift the point 
of a needle, and do not fuffer from a drop of wa. 
ter let fall from a confiderable height. If dry on- 
ly a quarter of an hour, the contac of water rée 
animates them; and in a little they become as 
vivacious 
