CLEANSING ORGANS. 177 



to know what is the use of the slender first pair, which 

 are also furnished with didactyle hands, but very 

 diminutive and feeble. See the Prawn, however, 

 washing himself after dinner, or at any other spare 

 moment, for he is careful to maintain his polished 

 coat of mail most scrupulously clean. You will then 

 see that the front feet are cleansing organs. They 

 are beset with hairs which stand out at right angles 

 to the length of the limb, radiating in all directions, 

 like the bristles of a bottle-brush. You will not see 

 them to advantage, it is true, in dried specimens; but 

 in a living state, or even when preserved in spirits, 

 they are conspicuous enough under a lens. These 

 are the Prawn's washing brushes, especially applied to 

 the cleansing of the under Surface of the thorax and 

 abdomen. When engaged in this operation, the ani- 

 mal commonly throws in the tail under the body, in 

 that manner which we see assumed in the pink speci- 

 mens that are brought to table, which is not, however, 

 the ordinary posture of life, the body being nearly 

 straight. Then he brings his forefeet to bear on the 

 belly, thrusting the bottle-brushes to and fro, and into 

 every angle and hollow with zealous industry, with- 

 drawing them now and then, and clearing them of 

 dirt by passing them between the foot-jaws. The 

 reason of the inbending of the tail is manifest ; the 

 brushes could not else reach the hinder joints of the 

 body, and still less the swimming plates ; but by 

 this means every part is brought within easy reach. 

 Sometimes the brushes are inserted between the edge 

 of the carapace and the body, and are thrust to and 

 fro, penetrating to an astonishing distance, as may be 



