TEE LOBSTER AND OTHER CRUSTACEANS. 81 



protected from injury. It is interesting to watch a live lobster when it 

 feels at home in an aquarium, and to see the lively motions of its eyes, 

 feelers, and jaws, as well as to watch it crawl over the bottom. But 

 the lobster is seldom to be seen in confinement. Shrimps, however, 

 which are much like lobsters, can be easily procured, and kept in 

 saucers, and also the crayfish, if the pupil lives far from the sea-shore. 



Behind the eyes are two pairs of feelers, called antennae ; each an- 

 tenna is composed of many small joints. It will be seen that the 

 first pair of antennae is small, and ends in two slender branches ; but 

 the second pair is very large, and over half as long as the body. In 

 life the antennae are kept in constant motion, as a blind man uses his 

 cane while walking, and they serve as feelers to detect the presence of 

 food or of enemies. The pupil should remove the antennae and lay 

 them on the table. 



And now for the jaws and other mouth-parts* and legs. For conve- 

 nience we will begin with the latter. The five paira of legs should be 

 removed and laid upon the table, one behind the other, beginning 

 with the pair of great claws. It will be seen that the three front pairs 

 of legs end in claws or nippers, and that each leg is composed of 

 seven joints. 



We are sorry to say that the lobster is a quarrelsome fellow; with 

 its great powerful claws it bites whatever comes in its way ; and in 

 duels with each other, which are only too frequent, they will not only 

 pinch and bile each other, but even go so far as to pull each other's 

 claws off. Fortunately, however, for the sufferer, a new claw will 

 grow out after a few weeks. 



If the class is a large one and there are a good many lobsters on the 

 table, it will be seen that one claw is always larger than the other, and 

 that sometimes it is the left and sometimes the right ; there is no rule 

 about it. 



If the legs have been removed, not roughly pulled ofiE, but carefully 

 dissected with the point of a knife, the gills will come off with them. 

 These are well worth examination. They consist of three branches, 

 each with hundreds of little slender cylindrical tubes. They are 

 packed away under the shisld against the sides of the body. The 

 gills are bathed by the fresh sea-water which passes in between the 

 shield and the side of the body; and in order to cause the water to 

 flow forward over the gills, a set of large paddles, which we may 

 call gill-paddles, by their movements keep the water in motion. 



* It is not necessary for the pupO to learn the names of these parts 

 of the mouth limbs, but the teacher should thoroughly know them. 

 They are explained in the author's Briefer Zoology (Henry Holt & 

 Co.). 



6 



