102 INTRODUCTION. 



shape and general character. The first, or great toe, analogous to the 

 thumb (though not antagonizing with its fellows), consists of two pha- 

 langal portions ; the others, of three. 



With regard to the lower Mammalia, the number of bones forming the 

 tarsus, and the general figure of this part of the foot, are very variable. 

 In many instances two bones are found consolidated into one, which, in 

 the human, subject, are distinct ; in some, bones present in Man are 

 absent ; in others, one or more supplemental bones are present. The 

 Camel and the Horse, for example, have only two cuneiform bones ; in 

 the ruminants generally, the os naviculare and os cuboides form a single 

 bone ; in the Daman the internal cuneiform bone is wanting. In the mo- 

 notrematous marsupials, and in most of the rodents, there are supple- 

 mental tarsal bones ; and in many of the latter the os naviculare is 

 divided : in all, however, the os calcis and the astragalus are present, and in 

 most instances the os calcis projects considerably. In the Pachydermata 

 and Ruminantia its elongation is remarkable : it receives a tendon analo- 

 gous to the tendo Achillis in Man, and commonly termed the hamstring. 

 The astragalus is remarkable for the deep pulley-like articulation, by means 

 of which it is united to the tibia : in the Horse, Elephant, and Daman, 

 it is united, anteriorly only, to the os naviculare ; in the ruminants, also ; 

 in the Hog, Rhinoceros, and Hippopotamus, it is united also to the cuboid. 



As there is great difference between the general contour and the 

 destined uses of the hands and the feet of Man ; while, on the contrary, 

 from a sameness of use, the anterior and posterior paws, or feet, of the 

 lower Mammalia, resemble each other, excepting in very minor particulars 

 (as the number of digits, &c.) ; it follows, that the metatarsal bones, and 

 phalanges of each pair, in the latter, will be mere copies of each other, or, 

 at least, exhibit but trifling variations. To this remark, the pedimanous 

 marsupials (as the Phalangers), in which the hind feet are furnished with 

 an opposable thumb ; the Kangaroos, Gerboas, Viscacha, and others, in 

 which the fore limbs are short, and the hinder limbs greatly developed ; 

 the Bat, in which the reverse exists ; and the Mole, which has the fore 

 feet constructed as spades, &c., are exceptions. In the Quadrumana, the 

 posterior pair are as truly prehensile as the anterior, perhaps more 

 so ; the thumb, in many genera, as the Lemurs, and various American 

 Monkeys, being better developed in these hinder hands than in those 

 which terminate the arms. 



In the Simise, as in Man, the number of the tarsal bones is seven ; in 

 the solidungulous animals it is six ; in the ruminants, five, with the ex- 

 ception of the Camel, in which it is six, and of the Giraffe, in which it is 

 four. In the Hog, Tapir, Elephant, Hippopotamus, Rhinoceros, &c., it 

 is seven ; but, in the Daman, only six. 



In the tarsus of the Ornithorhynchus nine bones are found : four in the 



