THE TYPICAL FROGS 



2635 



rocks of Bombay. Fossil frogs belonging to the typical genus Rana occur in the 

 lower Miocene rocks of Europe. 



' ' One of the most curious and interesting reptiles which I met with 

 in Borneo," writes Mr. Wallace, " was a large tree frog, which was 

 brought me by one of the Chinese workmen. He assured me that he had seen it 

 come down, in a slanting direction, from a high tree, as if it flew. On examining 

 it, I found the toes very long, and fully webbed to their very extremity, so that 

 when expanded they offered a surface much larger than that of the body. The fore- 

 legs were also bordered by a membrane, and the body was capable of considerable 

 inflation. The back and limbs were of a very deep shining green color, the under 

 surface and inner toes yellow, while the webs were black, rayed with yellow. The 

 body was about four inches long, while the webs of each hind-foot, when fully ex- 

 panded, covered a surface of four square inches, and the webs of all the feet together 

 about twelve square 

 inches. As the extrem- 

 ities of the toes have 

 dilated discs for adhe- 

 sion, showing the crea- 

 ture to be a tree frog, it 

 is difficult to imagine 

 that this immense mem- 

 brane of the toes can be 

 for the purpose of swim- 

 ming only, and the ac- 

 count of the Chinaman, 

 that it flew down from 

 the tree, becomes more 

 credible." The species 

 referred to is the Bor- 

 nean flying frog (Rhaco- 

 phorus pardalis) , a mem- 

 ber of a large genus, of 

 which another repre- 

 sentative (R. reinwardtt) 

 is shown in the illustra- 

 tion on p. 2634. Of the 

 forty-two species of the 

 genus, thirty occur in 

 South and East Asia, 

 and the remaining 

 twelve in Madagascar. 

 While allied in most re- 

 spects to the water frogs, they all differ by the presence of a small additional bone 

 between the terminal and penultimate joints of the toes, and likewise by the pe- 

 nultimate joints being distinctly marked externally as a kind of ridge; while 



VARIABLE TREE FROGS. 

 (Natural size.) 



