542 
Crustacea. 
§ II. Crustacea. 
THE LOBSTEK, (Astacus marinus,) 
Has a cylindrical bod}'', long antennae, and a broad tail. 
Its large claws enable it to seize on its prey, to fix itself 
on the small prominences of rocks in the sea, to resist 
the motion of the waves, and to defend itself against its 
enemies. When the Lobster wants to spring off the 
rocks, it makes a fulcrum of its tail, which has the 
action of a powerful spring. Its gait is awkward, as in 
all the Crustacea. Besides its claws, it has four small 
legs on each side, to assist it in its movements. Under 
the tail the hen Lobster preserves her eggs till they are 
hatched. They are extremely prolific. Dr. Baxter 
says he counted twelve thousand four hundred and 
forty-four eggs under the tail of a female Lobster, be- 
sides those that remained in the body undeveloped. 
Like the rest of their tribe, they cast their shells an- 
nually, previous to which they appear languid and 
restless : they acquire an entirely new covering in a 
few days. 
