362 BULLETIN 120, UNITED STATES NATIONAL MUSEUM. 



see later, that Papua had some connection with Malaysia after Papua 

 and Australia had finally parted. Papuan paleogeography seems to 

 need restudy. The Pelobatidae are apparently a decadent family 

 and seem to be holding on chiefly through their adoption of a semi- 

 subterranean habit. 



The BuFONiDAE (fig. 225, p. 289). 



The Bufonidae are cosmopolitan, within their temperature limits, 

 except for Papua, New Zealand, and Madagascar. They are prob- 

 ably descended from ancestors common with the Pelobatidae. Thej" 

 probably arose in the eastern portion of Equatoria, late in the Tri- 

 assic (fig. 232, p. 297), just before the Pelobatidae were evolved and 

 just before the separation of Australia. Some of the family spread 

 westward by the Equatorian route to India, Africa, and South 

 America and the genera characteristic of these regions evolved. An- 

 other group of genera arose in Australia. The family seems not to 

 have spread during the Jurassic (fig. 233) from Australia to conti- 

 nental Asia, since no genera other than Bufo are known from Asia 

 north of India, and we shall soon see reason to believe that Bufo is 

 post-Jurassic in origin. 



Bufo (fig. 226) apparently is more modern, having been derived 

 doubtless from some Equatorian form. It is now wholly absent from 

 Australasia, so could not well have been in Antarctica when this 

 continent was connected with Australia. No genera of the Bufonidae 

 other than Bufo are known from Asia north of the Himalayas, so 

 Bufo probably did not arise in Palearctica. Where did Bufo arise ? 

 Not in Australasia, for no Bufos are now living in this region. Not 

 in Africa before Madagascar separated from Africa (late Cretaceous, 

 fig. 235, or early Tertiary, fig. 236) , for no Bufos are in Madagascar. 

 Not in India, according to Arldt, for fossil Bufos are known from 

 the Oliogooene of Europe, which is earlier than the establishment 

 of connection between the Indian island and continental Asia (figs. 

 236, 23Y). 



There are two other regions in which there are or have been genera 

 of Bufonidae from which Bufo may have been derived. These re- 

 gions are Malaysia and northern South America. First as to Malay- 

 sia. Common ancestors of the Pelobatids and Bufonids, originally 

 eastern Equatorian forms, were probably in Malaysia during the 

 Jurassic (fig. 233). From these, on the north, developed the Pelo- 

 batids occupying continental Asia. Bufo may have arisen at the 

 same time, moving north into continental Asia along with the Pelo- 

 batids. This apparently would have been during the early Creta- 

 ceous, just as Australia was breaking away from Malaysia. Bufo 

 may then have moved into all of Asia and into Europe during the 



