268 



REPTILIA. 



short and broad ; the others are all long and 

 slender. The little finger has only two pha- 

 langes, and is not longer than the thumb, so 

 that the whole hand has a pointed shape. The 

 thumb and the index finger only have their 

 last phalanx armed with a nail. 



In the land tortoises {fig, 181.), itisneces- 



Fig. 181. 



-Anterior extremity of the Tortoise. 



sary to admit that there are only two phalanges 

 to each finger, or else to suppose, either that 

 the last row of carpal bones is wanting, or that 

 the metacarpal bones are deficient. By compa- 

 rison, however, with the hands of fresh-water 

 tortoises, it is evident that the bones present 

 belong to the carpus and metacarpus. 



This being allowed, the carpus is found to 

 consist of a large radial or scaphoido-semi- 

 lunar bone ('), of two ulnar bones (c, d.), 

 which are nearly of a square shape, of five 

 bones of the second row (1, 2, 3, 4, 5,) sup- 

 porting the metacarpal bones, and of an inter- 

 mediate bone (e), situated between the great 

 radial (a'), the first cubital, and those which 

 support the third and fourth metacarpal bones. 

 This intermediate bone is very frequently con- 

 solidated with the great scaphoido-semilunar 

 bone, as represented in the figure. 



The bones of the metacarpus in these 

 tortoises are even shorter than the phalanges. 



Hind Feet. In the Chelonians, the os 

 calcis does not project posteriorly, so that 

 the tarsus is as flat as the carpus. In the 

 turtles (fig. 182.), it is composed of six or 

 seven bones, according as the last is reckoned 

 as belonging to the tarsus or to the little toe. 

 Two constitute the first row, of which the 

 larger ('), which is nearly of a rhomboidal 

 shape, and connected both to the tibia and 

 fibula, is the astragalus ; the smaller (6), con- 

 nected to the fibula alone, is the only repre- 

 sentative of the os calcis. 



In the second row there are four pieces, 

 three of which are cuneiform bones, support- 

 ing the metacarpal bones of the great toe, and 

 of the two following ones ; and the fourth, 

 which is of larger size, appropriated to the 

 two last metatarsals. 



The metatarsal bones of the great toe and 

 of the little toe are singularly broad and flat ; 

 indeed, that of the little toe (c) might be 

 taken for one of the tarsal bones a little 

 removed from its place, in which last case the 

 little toe would consist of only two phalanges : 

 according to the former supposition it would 



have three like the middle ones. The thumb 

 or great toe has but two ; it is furnished with 



Fig. 182. 



Hind-foot of Trtonyx. 



a nail at its extremity, as well as the finger 

 which is next it ; the two following have 

 their terminal phalanges large but without 

 nails ; the last phalanx of the little toe is 

 very small. 



In the land-tortoises the analogue of the 

 Fig. 183. 



Hind-leg of Tortoise. 



astragalus is more bulky and thicker, whilst 

 the fibular bone or analogue of the os calcis 

 is proportionally smaller. The other four 

 tarsal bones are present, and in this case that 

 which supports the little finger seems to form 

 one of the series, both from its position and 

 its shape ; sometimes it supports a rudiment 

 of a little toe consisting of one piece only, 

 but in many species this is wanting. 



The metatarsal bone of the great toe is 

 short but not flattened ; the others are a 

 little longer : none of the four toes have more 

 than two phalanges. 



In the Chelonian reptiles, the os hyoides 

 varies very remarkably as to its form in 



