36 EVERS'S COMPARATIVE ANATOMY. 



point below. Ruminants, on the contrary have the fibula better 

 developed inferiorly where it forms the external malleolus and ex- 

 tends but a short way up the leg. Pachyderms, and all the ungili- 

 Gulata, possess a fibula well developed ; and in sloths its lower 

 extremity ends in a conical point, which enters a corresponding 

 cavity in the astragalus. In the rodentia, and insectivora, particu- 

 larly the mole, the tibia and fibula are united through their inferior 

 half. Carnivora have these bones fully developed and detached: 

 this is well seen in the phocidee and felina?. In the dog they are 

 united posteriorly. 



Tarsus. — The bones composing this part of the foot for the 

 greater part resemble those of man. The cheiroptera present a 

 remarkable peculiarity in the formation of a long slender bone, 

 extending from the back of the os calcis half way to the tail, and 

 enclosed within the flying membrane. Cuvier and Meckel supposed 

 it to be a portion of the os calcis, whilst Daubeton conceived it to 

 be a distinct bone. On the inner side of the tarsus of the mole, a 

 sickle-like process of bone is found, similar to that observed on the 

 carpus. The metatarsus and toes in ruminants and solipeds are 

 disposed pretty nearly as in the anterior extremities. The rodentia 

 and carnivora have usually five toes, the great one being often 

 shortened, or as in cats, dogs, and hares, altogether absent. The 

 quadrumana and marsupiales have the great toe separated from the 

 rest, bearing the same relation to the foot as the thumb to the hand. 



Although the disproportion in the respective size and length of 

 the upper and lower extremities of the human subject, indicate the 

 different functions they are designed to execute, yet they present 

 many similarities throughout their divisions, the construction of 

 their articulations, and the number and form of their bones. The 

 arm, fore-arm, and hand, lor instance, resemble the thigh, leg, and 

 foot; the os innominatum may be compared to the scapula; the 

 hip, knee, and ankle, to the shoulder, elbow, and wrist: and the 

 carpus, metacarpus, and fingers, to the tarsus, metatarsus, and toes. 

 Contrast. — A line falling perpendicularly from the shoulder in the 

 erect attitude, would pass behind the hip. The upper extremities 

 diverge below, whilst the inferior converge. The deep acetabulum, 

 and the strong tight capsule of the hip, may be well contrasted 

 with the shallow glenoid cavity, and weak, loose capsule of the 

 shoulder. The lower extremities are as long as the head and 

 trunk together, being only equaled in this respect by the kangaroo 

 and jerboa. 



The great length of the shaft and neck of the femur, its perpen- 

 dicularity with the spine, and the depth of its internal condyle, are 

 characters peculiar to man : in the fore-arm every thing conspires 

 to procure freedom of motion; in the leg, strength and security are 

 the objects aimed at. The hand is articulated on a line with the 

 fore-arm, and enjoys free and varied motions; the leg joins the 

 foot at a right angle, and moves chiefly in the angular direction; 

 the entire surface of the tarsus, metatarsus, and toes, rests on the 

 ground : the two latter circumstances are exclusively confined to 



