100 



ANATOMY OF VERTEBRATES. 



Hi, metatarsals. The ectocuneiform, f, 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- 

 120 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- 

 ponding metacarpals. That of 

 the first toe, i, 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 iv, 

 are webbed in true Crocodiles, 

 but semipalmate in Alligators. 

 In most Lacertians two verte- 

 bra? 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, f, 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, Crocodile 



