PTERODACTYLE. 177 



As the bones in the wing of the Pterodactyle thus agree 

 in number and proportion with those in the fore-foot of the 

 Lizard, so do they differ 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 com- 

 pare the number and proportion of the joints in these four 

 toes with those of Lizards, (PL 22, f, g, h, 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 proportions are also pre- 

 cisely the same, as in the feet of Lizards.f The apparent 



rostris, (PJ. 22, n, 44, 45,) the fifth finger was elongated to expand the 

 wing, we sliould infer from the normal number of joints in the fifth finger 

 of Lizards being only three, that tills wing finger had but tiiree joints. In 

 the fossil itself the first two joints only arc preserved, so that his conjectural 

 addition of a fourth joint to the fifth finger, in the restored figure, (PI. 22, 

 A, 47 ) seems inconsistent with the analogies, that pervade the structure of 

 this, and of every other species of Pterodactyle, as described by Cuvier. 



* 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 metacarpal bones, (26 — 29,) much elongated and 

 terminated by tlie minute 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, the Pterodactyle affords 

 with respect to the hand of Lizards. 



+ According to Goldfuss the P. Crassirostris had one more toe than Cuvier 

 assigns to the other species of Pterodactyles; in this respect it is so far from 

 violating the analogies we are considering, that it adds another approxi- 

 mation to the cliaraett-r of the living Lizards; we have seen that it also differs 

 from the other Pterodactyles, in having the fifth, instead of the fourth finger 

 elongated, to become the expansor of the wing. 



It is however probable that the fifth toe had only three joints, for the 



