fo) CHORDATA. 
he proximal carpal bones are the radiale, intermedium 
id ulnare, together with the centrale (which in some cases 
is paired), whereas the proxi- 
Fig. 301.—D1aGRaM OF mal tarsals are tibiale, inter- 
eee medium and fibulare, and also 
cha acentrale. In each limb there 
follow five distal carpalia and 
tarsalia, each of which bears 
a metacarpal or metatarsal, 
followed by the phalanges of 
the fingers or toes. The primi- 
tive position of the limbs is 
not retained, but they become 
altered. Firstly, they are bent 
into a Z-shape by a bend 
downwards between the proxi- 
mal bones and the distal and 
a bend upwards between the 
latter and the carpals or tarsals. 
The limbs still protrude out- 
wards at right angles to the 
body, a condition still pre- 
served in many reptiles with 
shuffling gait. Secondly, the 
upper joint (knee or elbow) 
becomes deflected 
ga 10N ’ inwards towards 
cr ense rans the body, . the knee 
Ge! oo ; Jorwards and the 
A ee elbow  Jbackwards, 
METACARPALS : ‘ 
| ia bringing the post- 
PROXIMAL EXTREMITY 
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axial bones to the 
f oo PULANBES Outside. The feet 
vA ! \ Ye are at the same time, 
V in each case, twisted 
f \ forwards through go” 
0 ' V so as to face forwards. 
In the hind limb the 
foot and the upper 
DISTAL EXTREMITY part of the limb are 
therefore both bent 
