“I believe it is the same place as the painted picture,” said I.

“It is the same place,” the Professor answered.  “I found traces of the fellow’s camp.  Now look at this.”

It was a nearer view of the same scene, though the photograph was extremely defective.  I could distinctly see the isolated, tree-crowned pinnacle of rock which was detached from the crag.

“I have no doubt of it at all,” said I.

“Well, that is something gained,” said he.  “We progress, do we not?  Now, will you please look at the top of that rocky pinnacle?  Do you observe something there?”

“An enormous tree.”

“But on the tree?”

“A large bird,” said I.

He handed me a lens.

“Yes,” I said, peering through it, “a large bird stands on the tree.  It appears to have a considerable beak.  I should say it was a pelican.”

“I cannot congratulate you upon your eyesight,” said the Professor.  “It is not a pelican, nor, indeed, is it a bird.  It may interest you to know that I succeeded in shooting that particular specimen.  It was the only absolute proof of my experiences which I was able to bring away with me.”

“You have it, then?” Here at last was tangible corroboration.

“I had it.  It was unfortunately lost with so much else in the same boat accident which ruined my photographs.  I clutched at it as it disappeared in the swirl of the rapids, and part of its wing was left in my hand.  I was insensible when washed ashore, but the miserable remnant of my superb specimen was still intact; I now lay it before you.”

From a drawer he produced what seemed to me to be the upper portion of the wing of a large bat.  It was at least two feet in length, a curved bone, with a membranous veil beneath it.

“A monstrous bat!” I suggested.

“Nothing of the sort,” said the Professor, severely.  “Living, as I do, in an educated and scientific atmosphere, I could not have conceived that the first principles of zoology were so little known.  Is it possible that you do not know the elementary fact in comparative anatomy, that the wing of a bird is really the forearm, while the wing of a bat consists of three elongated fingers with membranes between?  Now, in this case, the bone is certainly not the forearm, and you can see for yourself that this is a single membrane hanging upon a single bone, and therefore that it cannot belong to a bat.  But if it is neither bird nor bat, what is it?”

My small stock of knowledge was exhausted.

“I really do not know,” said I.

He opened the standard work to which he had already referred me.

“Here,” said he, pointing to the picture of an extraordinary flying monster, “is an excellent reproduction of the dimorphodon, or pterodactyl, a flying reptile of the Jurassic period.  On the next page is a diagram of the mechanism of its wing.  Kindly compare it with the specimen in your hand.”