73 o THE POPULAR SCIENCE MONTHLY. 



of opinion that these flying dragons " had a brain indistinguishable from 

 a bird's." 



They are all remarkable for their great proportionate length of head 

 and neck, for in some the lizard-like and in others the birdlike length 

 of tail, and for the large size of the fore-limb, which, quite unlike the 

 same extremity in a bird, was terminated by four digits, whereof three 

 were clawed, while the clawless fourth or little finger was enormously 

 elongated to support the outer edge of an expansion of the integument 

 like the wing of a bat. The bones of the hind-limb and of the haunch 

 differ widely from the bird type ; nevertheless, air-passages, such as 

 characterize no other kind of skeleton, are met with in the bones of the 

 head, of the spine, and of the fore and hind limbs, often coinciding 

 identically in situation with those in birds, and indicate, according to 

 Prof. Seeley, a system of air-circulation from the lungs similar to what 

 is found in birds. From this he argues the existence in these gigantic 

 volants of warm blood, and of a heart similar to the bird's in construc- 

 tion. They have the breastbone broad, strongly keeled, and unlike 

 that of other reptiles ; there is evidence also that the jaws were in- 

 cased in a horny sheath. On these considerations, therefore, it is held 

 that, as far as the skeleton indicates, their differences from birds are 

 much less than the differences between the several orders of mammals 

 or reptiles. The same paleontologist has made careful casts of the in- 

 terior of the skull, and, from the position of certain lobes whose dis- 

 tance or proximity distinguishes the brains of modern birds and rep- 

 tiles, he says in an interesting paper on the subject in the Linnaean 

 Society's "Transactions" for 1876: "The resemblance of form and 

 arrangement of parts between this fossil animal's brain and the brain 

 of a bird amounts, as far as the evidence goes, to absolute identity ; no 

 more perfect specimen could add to the force of the conclusion that its 

 brain is an avian brain of a typical structure. Since brain and lungs 

 are organs of incomparably greater value in questions of organization 

 than fore and hind limbs organs in which, according to Prof. Huxley, 

 they depart most widely from the bird type the flying dragons on the 

 whole are very reptilian birds rather than very avian reptiles." 



The Solenhofen stone preserves not only bones and hard parts, but 

 even the cutaneous characters of its old inhabitants. It shows casts of 

 the down and feathers, impressions of the fine foldings or wrinkles of 

 thin expansions of naked skin, as well as of delicate tendons. Prof. 

 Owen, therefore, thinks that if the flying dragons had possessed any 

 plumose clothing it would in all probability have been preserved, and, 

 as no such indications (but contrariwise, several genera undoubtedly 

 had their body-covering hardened into bony scales, sometimes pro- 

 duced into prodigious spines) have been discovered, though the Oolitic 

 mud has entombed the greatest number and variety of these beings, he 

 concludes that they were cold-blooded, as other reptiles are ; whereas, 

 if they had been warm-blooded, they would have possessed feathers, as 



