526 PHILOSOPHY OF ZOOLOGY. 



The hip, or coxa, serves to unite the limb with the body. 

 It is usually short, or nearly as broad as it is long. It 

 is imbedded in the body, and is limited in its motion by 

 the mode of insertion. Sometimes its proximal extremity 

 is globular, and received into a corresponding cavity of the 

 body, giving to it a very extensive degree of motion. In 

 other cases, the coxae are consolidated with the skin. 



The thigh or femur is usually united with the coxa, in 

 such a manner as only to admit of motion backwards and 

 forwards. At its coxal extremity, k the femur has, in some 

 tribes, one or two eminences, in some cases produced into 

 spines, which are termed trochanters, and as they are hol- 

 low within, they are considered as furnishing suitable inser- 

 tions to the muscles for particular motions. When the 

 thigh is slender and cylindrical, the motion of the legs is 

 confined to walking, but where leaping is required, or even 

 swimming, the thigh is thick, and bellied, to give room to 

 the requisite muscles 



The leg, or tibia, is articulated to the femur in such a 

 manner as to admit of motion only in the same plane in 

 which it moves. In those species which swim, this joint is 

 long and flattened, while, in those which dig holes in the 

 ground, it is strong and serrated on the margin. 



The toe, or tarsus, consists of several joints, which are 

 articulated more loosely than the preceding parts of the 

 limb, and admit not only of motion outwards and inwards, 

 but likewise in a lateral direction. Its strongest muscle, 

 as in the other parts of the leg, is the flexor. It is only by 

 means of this part that the feet can apply closely to any 

 object. The joints vary in number, length, and size ; and, 

 in many species, are furnished with very singular appendi- 

 ces. Those in insects which deserve particular notice are 

 denominated cushions and suckers, and are situate on the 

 under surface of the joints. The cushions are either soft 



