206 LIFE, IN ITS INTERMEDIATE FORMS. 



among the number, arranged them under the great class 

 Insecta. They have, however, a greater number of limbs; 

 the full provision being five pairs of true feet, and three 

 pairs of organs, which (because of a certain ambiguity in 

 their function, like that useful piece of furniture of which 

 we read — 



"Contrived a double debt to pay, 



A bed by night, a chest of drawers by day,") — 



are called foot-jaws. Besides these, a great number of the 

 species have five or sis pairs of jointed limbs attached to 

 the under-side of the abdomen, which are generally used 

 for progression, and are called false-feet. Their mouth is 

 furnished with three pairs of jaws and two pairs of an- 

 tennse. It must be borne in mind, however, that the total 

 complement of these members is not found present in 

 every species, some of them being wanting in certain 

 extensive groups. 



The researches of a naturalist who has paid much atten- 



Prawn. 



tion to this class, Mr Spence Bate, have shed a flood of 



