THE FORE-LIMB. 57 
prominent condylar ridge, the inner or postaxial 
one being the larger of the two, especially in the 
male frog. 
b. The fore-arm. 
i. The radio-ulna: corresponding to two bones, radius 
and ulna, in other animals: it is single at its 
proximal end, but in its distal halfis imperfectly 
divided by a groove into anterior or radial, and 
posterior or ulnar portions. Its proximal end is 
hollowed out to articulate with the lower end of 
the humerus, and so form the elbow joint, be- 
hind which it forms the backwardly projecting 
olecranon process. 
c. The wrist; consists of six small carpal bones arranged 
in two rows, proximal and distal, each row having three 
bones. 
d. The hand; has four complete digits and a rudimentary 
pollex or thumb. Each digit consists of a proximal 
metacarpal bone, beyond which are a variable number 
of phalanges. 
i. The pollex: the anterior or sical digit : consists 
simply of a small metacarpal bone. 
ii. Corresponding to the fore-finger of man: consists 
of a metacarpal and two phalanges. 
iii. Corresponding to the middle-finger of man: consists 
of a metacarpal and two phalanges. 
iv. Corresponding to the ring-finger of man: consists 
of a metacarpal and three phalanges. 
v. The postaxial digit, corresponding to the little-finger 
of man: consists of a metacarpal and three 
phalanges. 
3. The pelvic girdle. 
Consists primitively, like the pectoral girdle, of a couple of 
half-rings of cartilage, fused together below and attached above 
to the tips of the transverse processes of the sacrum. In the 
adult frog the girdle is placed very obliquely so as to be nearly 
parallel with the vertebral column instead of at right angles 
to it. 
