INSECTS CRUSTACEA DIAGRAM 7. 153 



There are live pairs of legs, but the first are much larger than 

 the others, and resemble strong pincers. The abdomen is com- 

 posed of several rings, below which are a kind of limbs called 

 false legs. It is to these that the female attaches her eggs, 

 which she carries everywhere with her. On raising the edges 

 of the hard part, or carapace, which covers the head and thorax, 

 we find on each side, five branchiae branching like trees. 



The crayfish which appear to be so well enclosed in their hard 

 skins, nevertheless change them every year. When the time of 

 moulting arrives, the carapace detaches itself from the first 

 segment of the abdomen, and splits in the middle at the same 

 time; and the crayfish giving a violent jerk, gets out of its old 

 skin with an entirely new one. This is not yet as hard as the 

 other, but quite soft ; the animal then hides itself in some hole ; 

 until at the end of a few days, its new skin becomes hard, when 

 it resumes its former mode of life. The crayfish, like most 

 Crustacea, is carnivorous. 



The lobsters are nearly of the same shape as the crayfish, but 

 they are much larger, reaching a foot or more in length, and ten 

 or twelve pounds in weight j they live in the sea. During life,, 

 they are of a bluish black colour. 



The crabs are perhaps the most abundant of all Crustacea. The 

 sea-shore swarms with them. They feed on all the dead animals 

 and carcasses which are cast up on the beach. They are found at 

 low tide under stones. Some are very active, and run away side- 

 ways. The common edible crab is very large, and has been known 

 to weigh as much as twelve pounds. But they move little and 

 conceal themselves in the crevices of rocks, and under seaweed. 



Shrimps and prawns are very small Crustacea which are much 

 valued for the table, and swim with great agility in the water. 

 They fish for them at low tide on the sand, with a net with very 

 narrow meshes. 



All Crustacea similar to these which we have mentioned turn 

 red when cooked, but very few are of this colour while living. 



The woodlice, which live in damp places, are also Crustacea ; 



