230 THE ANIMAL KINGDOM. 



of carbonate of lime (chalk) held together by animal matter. 

 The greater part of the Crustacea inhabit the waters, and 

 they cast their shells from time to time as they grow ; the 

 Lobster (Astacus marinus), is a familiar example, it is 

 found in the sea near rocky shores, and is capable of rapid 

 motion under the water, darting along (tail foremost) with 

 great rapidity, it has powerful claws, with one of which (the 



HG. 15. CEUSTACEA. 



1. Lobster (Astacus marinus). 3. Crab (Cancer pagurus). 



2. Cray-fish (Astacus fluviatilis). 4. Shrimp (Crangou vulgaris). 



5. Prawu (Palremon serratus). 



blunt one) it holds its food and with the other (the sharp 

 one) cuts it up into pieces ; they have the power of casting 

 off these claws and reproducing them; they feed upon 

 smaller Crustacea and fish, or any animal matter they can 

 find. The Cray-fish is another example, it is a sort of fresh- 

 water Lobster, living in holes (frequently deserted rat holes) 

 in the banks of rivers ; its shell is very rough, but otherwise 

 somewhat resembles the Lobster. Crabs, Shrimps, and 

 Prawns, are members of this class (fig. 15). 



