FROGS AND THEIR USES. 185 



sticking to tlie tongue, it is with marvelous rapidity ■whipped 

 back to the frog's throat and swallowed. Frogs will also seize 

 some of their prey in other ways, and for this purpose they use 

 their jaws and teeth, which latter are to be found on the palate 

 and upper jaw. I have frequently taken them with hook and 

 line, the former being baited only with a small piece of red flan- 

 nel. So far as I know at present there is no species of frog that 

 has come to the knowledge of science that possesses a poison gland 

 or apparatus. Some of them, however, secrete from their skin 

 pungent and disagreeable secretions. These are protective in a 

 way, and prevent other animals from preying upon them. In a 

 species of Hyla I met with upon the island of Cuba this secretion 

 was so strong as to bring water to the eyes, and upon one occasion 

 when handling one of these creatures and then rubbing my eyes 

 the lids of the latter swelled tremendously, and this condition 

 was only reduced after proper treatment lasting over three or four 

 days. There is another tree frog {Hyla micans) in which this 

 secretion of the body is slimy and profuse, and it at the same time 

 possesses luminous properties, which probably also serves to pro- 

 tect the animal from its enemies. There are many beautiful ex- 

 amples of protective mimicry to be seen among frogs, especially 

 among the brown or the green tree frogs, or other arboreal forms 

 that are mottled and shaded with greens, grays, and browns. 

 These species usually feed at night and are still all day, being 

 detected only with difficulty, as they rest upon leaves, limbs, or 

 rocks. Some are brilliantly colored, but they are nonedible varie- 

 ties, and so their high-colored skins serve them as a protection. 



Fossil frogs first occur in the Tertiary, but they become more 

 abundant in the Miocene period. 



A SCIENTIFIC way to settle international boundary disputes is suggested 

 by Mr. Hugh Robert Mill, who, speaking of the proposal of the Interna- 

 tional Geographical Congress for a series of official maps on a uniform 

 scale, says, in Nature : " If the governments of all countries were jointly to 

 take this matter up, survey all unsurveyed lands which they claim, and 

 submit tlie uncertain boundaries, which are yet uncomplicated by gold 

 mines, to an international commission of geographers, to be decided on the 

 basis of a new map on purely geographical principles, the expense would 

 be many times saved by the security which well-defined frontiers give, and 

 a magnificent contribution to science would be effected." 



The region of the delta of the Yukon is described by W. H. Dall, in his 

 paper on Alaska as it Was and Is, as remarkable for being the breeding 

 place of myriads of waterfowl, some of which are peculiar to the Alaskan 

 region. Nearly a hundred species gather there, and one of them comes all 

 the way from north Australia, by the coasts of China and Japan, to lay its 

 eggs and rear its young in this spot. 



TOL. XLIX. — 17 



