190 



ANATOMY OF VERTEBRATES. 



120 



Hi, metatarsals. The cctocuneiform, /, is wedged between the 

 bases of the second and third metatarsals. These, by the oblique 

 overlapping arrangement of their expanded bases, resemble the 



articulations of the ventral fin- 

 rays in most fishes. The fifth 

 is flattened and expanded to sup- 

 port the broad scale from the 

 outer side of the foot, but is 

 curtailed in length and supports 

 no toe. 



The four normal metatarsals 

 are much larger than the corres- 



o 



ponding metacarpals. That of 

 the first toe, z, is the shortest 

 and strongest; it supports two 

 phalanges : the other three are 

 of nearly equal length, but lose 

 thickness from the second, ii, to 

 the fourth, Hi: the second sup- 

 ports three phalanges ; the third, 

 four ; the fourth, also four, the 

 claw and its phalanx being ab- 

 sent in this toe : ii, Hi, and w, 

 are webbed in true Crocodiles, 

 but semipalmate in Alligators. 

 In most Lacertiaiis two verte- 

 brae are modified for articulation 

 with the iliac bones, as in the Mo- 

 nitor ( Varanus, fig. 121, a) : but 

 in the Chameleon there are three 

 sacrals. In the great Monitor 

 the ilium, b, extends backward 

 beyond the junction, terminat- 

 ing obtusely, and bends down 

 as it passes forward with a short 

 process above the acetabulum. 

 Both ischium and pubis com- 

 bine with the ilium in forming this cavity. The ischium, c, 

 is usually most expanded at its symphysial border, which is pro- 

 duced backward. The pubis, /, appears as a more direct con- 

 tinuation of the ilium, and is perforated near its acetabular end, 

 anterior to which it developes a process. The symphysial car- 

 tilage is continued from the ischium to the pubis, dividing the 



Bones of leg and foot, 



