CRUSTACEA. 
449 
the bottle when rainy weather is approaching, remain in 
the bottom in dry weather, and move themselves anxiously 
up and down when the weather is stormy. Horse Leeches 
are larger than the common ones, more voracious, and 
narrower at each extremity. The use of the Leech is well 
known in medicine, as by its means the blood is extracted 
from diseased parts, to which the lancet cannot be 
applied. 
SECTION III. rustaeea. 
THE LOBSTER (Astacus marinus,) 
Has a cylindric body, the antennas long, and a broad 
tail. Its large claws enable it to seize on its prey, to fix 
itself at the small prominences of rocks in the sea, to 
