128 EXTINCT MONSTERS. 
In order to give rapid movement to their wings during flight, 
they had powerful muscles in the region of the chest. ‘These 
were attached to a shield-like breast-bone provided with a keel— 
as in birds. But this bird-like feature is only a necessary pro- 
vision to enable them to fly, and does not point to any relation- 
ship. 
In the year 1873 was discovered, in the lithographic stone of 
Bavaria, at Eichstadt, a very beautiful new form of Pterodactyl. 
This was the Rhamphorhynchus phyllurus. The specimen is in a 
remarkable state of preservation; for the bones of the skeleton 
are nearly all in position, while those of both wings show very 
perfect impressions of the membranes attached to them. Its 
long tail supported another small leaf-like membrane, which was 
evidently used as a rudder in flight (see Fig. 35).’ The dis- 
FIG. 35.—Skeleton of Rhamphorhynchus phyllurus, with delicate impressions of 
the flying membranes. (After Marsh.) 
covery of this valuable specimen attracted much attention at 
the time. It was bought, by telegram, for Professor Marsh, and 
so secured for the Yale College Museum; but a cast may be 
seen at South Kensington (Wall-case, No. 1, Gallery IV. on plan). 
Any one who looks carefully at the beautiful impressions of the 
wings of this specimen can see that they must have been produced 
by athin smooth membrane, very similar to that of bats. When 
