REPTILIA. 
9 
and so preserve their original shape. An incomplete humerus „ ,, 2 - 
from the Chalk of Burham, Kent, in Table-case 3 is especially a ®"| ases 
noteworthy in this respect: where sharply cut across in D. 
three places it displays the extreme thinness of the dense 
bony wall, and also exhibits traces of an internal framework 
of delicate struts to strengthen the expanded upper end. 
Most of the English Cretaceous Pterodactyls ( Ornithocheirus ) 
were provided with large teeth in sockets, as shown by 
portions of jaws from both the Chalk and the Cambridge 
G-reensand. Some of their American contemporaries were 
also toothed. 
The Jurassic Pterodactyls are much smaller than those 
which followed them in the Cretaceous period. Some of the 
Fig. 5.— Restoration of a long-tailed Flying Reptile (Rhamphorhynchus 
phyllurus ), from the Upper Jurassic (Lithographic Stone) of Eichstatt, 
Bavaria ; one-seventh nat. size. (After O. 0. Marsh.) 
short-tailed forms ( Pterodactylus , Fig. 4), exhibited in Table- 
case 1, are, indeed, no larger than sparrows or thrushes. 
All are provided with teeth in sockets, and all have three 
complete fingers with claws adjoining the base of the wing- 
finger. Their first finger, or thumb, is commonly supposed 
to be reduced to the little spur of bone which turns inwards 
to support the piece of membrane originally extending from 
the shoulder to the wrist. A long-tailed form ( Rhamyho - 
rhynchus), with the slender-toothed jaws ending in front 
in a pointed toothless beak, is represented at the bottom of 
Wall-case 2 by several portions of skeletons from the Litho¬ 
graphic Stone of Bavaria. The grain of this stone is so fine 
that some specimens of Bhamphorhynchus have been found 
displaying impressions of the smooth wing-membrane. A 
