“What is it this time?” asked Jerry. “A pink-eyed toad or a blue-nosed grasshopper?” for the scientist was continually on the lookout for strange and rare insects or reptiles.

“Neither one,” answered Mr. Snodgrass, “but I have just found, in this book, an article telling about a strange double-tailed toad, very rare, which is said to be a native of New Mexico. It is a species of the horned toad, but very different. For years I have been investigating, trying to get on the trail of this sort of toad, and now, most unexpectedly, I come upon a clew. Boys, this has indeed been a fortunate day for me. I shall start right away for New Mexico. I must telegraph the college president at once that I can get a most valuable specimen to add to our collection. Oh, this is indeed fortunate!”

The professor was rapidly making notes from the article in the book. The boys looked at one another. Then Ned spoke.

“Fellows,” he said, “this just fits in. New Mexico is on the way to the Grand Canyon—or at least it won’t be much out of our way to go there. We can have a try for the radium fortune and at the same time the professor can look for his tailless toad. How about it?”

“Two-tailed toad! Two-tailed!” cried the little scientist. “Don’t make that mistake, Ned. But I think that will be a good plan. I was undecided about it before, but, since you are going, I will go with you, and I’ll do all I can to help you get to Snake Island.”

“And we’ll help hunt the two-tailed toad,” added Bob. “Now, how about you, Jerry?”

“Oh, I’m game. I’ll go along, but we’ve got to straighten out about our auto and motorship. First we’ll write to Mr. Glassford, asking him to hold the Comet in Denver for us. Then we must hurry the repairs on the auto.”

Mr. Glassford, as my old readers probably remember, was the man who first helped our heroes to construct their motorship. He had recently borrowed their latest and largest craft for exhibition purposes.

“Well, get busy,” advised Ned. “Here is some paper. Take my fountain pen and write some letters. It’s decided then; we’ll have a try for the radium, and we’ve got to get a move on to get ready.”

“Here comes the postman,” spoke Bob. “I’ll get the mail, Ned.”