PTEROUACTYLE. 
229 
As the bones in the wing of the Pteroclactyle 
thus agree in number and proportion with those 
in the fore foot of the Lizard, so do they difter 
entirely from the arrangement of the bones 
which form the expansors of the wing of the 
Bat.* 
The total number of toes in the Pterodactyles 
IS usually four; the exterior, or little toe, being 
deficient; if we compare the number and pro- 
[)ortion of the joints in these four toes with 
those of Lizards, (PI. 22, f, g, ii, i,) we find the 
agreement as to number, to be not less perfect 
than it is in the fingers ; we have, in each case, 
two joints in the first, or great toe, three in the 
second, four in the third, and five in the fourth. 
As to proportion also, the penultimate joint is 
always the longest, and the antepenultimate, or 
last but two, the shortest ; these relative propor- 
tions are also precisely the same, as in the feet 
of Lizards-t The apparent use of this disposi- 
The Bat, see PI. 22, m, 30, 31, the first finger or thumb 
alone, is free, and applied to the purpose of suspension and 
creeping; the expansors of the wing are formed by the meta- 
caipal bones, (26 — 29,) much elongated and terminated by the 
aiinute phalanges of the other four fingers, 32 — 45, thus 
presenting an adaptation of the hand of the mammalia to the 
purposes of flight, analogous to that which in the fossil world, 
t e Pterodaotyle aflbrds with respect to the hand of Lizards. 
t According to Goldfuss the P. Crassirostris had one more 
foe than Cuvier assigns to the other species of Pterodac- 
fylcs; in this respect it is so far from violating the analogies 
