446 BULLETIN 120, UNITED STATES NATIONAL MUSEUM. 



Honigmann (1921). A notice [not quite accurate] of Metcalf 

 1920, h) showing from the Anura and their Opalinid parasites the 

 importance of the evidence from such a double series of data bearing 

 upon questions of former intercontinental connections. 



Metcalf (1921,a) gives an abstract of a paper read before the 

 American Society of Zoologists, as follows : 



Geographical disf/Hhution of the Anura and theii' Opalinid para- 

 sites. The Amphibia give peculiarly valuable evidence as to land 

 migration routes, for they can not endure salt or even brackish 

 water. The Opalinids are parasitic exclusively in Anura, except- 

 ing three species, two of which are known from Urodeles and one, 

 strangely, from a marine fish. The author has studied 130 species 

 and 20 subspecies of Opalinids from all temperate and tropical por- 

 tions of the world, southern Asia being the only region outside the 

 northern and southern cold belts from which his material is not quite 

 abundant. Study of this material and comparison with the known 

 data as to the geographical distribution of the Anura indicates: 1, 

 That the Raninae are a northern and eastern hemisphere subfamily, 

 which have not reached Australasia (except for a single species at 

 the northern tip of Australia), and have not reached South America 

 (except for three species which have entered the northern Andes) : 

 2, That the Bufos arose in the northern hemisphere [the present 

 volume places the origin of Bufo probably in northwestern South 

 America or possibly in southeastern Asia] and were not present 

 in Antarctica, Patagonia, and Australia at the time when these 

 were united into an Antarctic continent, though the Bufos are 

 now in Patagonia : 3. That the Leptodactylidae arose in Patagonia, 

 at a time when Patagonia was not connected with tropical America, 

 and spread via Antarctica to Australia: 4, That later than this, 

 Patagonia having separated from Antarctica and having united with 

 tropical America, the Bufos passed southward into Patagonia and 

 the Leptodactylids passed northward into tropical America. When 

 the Bufos and Leptodactylids met, the Bufos adopted the Lepto- 

 dactylid Opalinids, while the Leptodactylids did not adopt the 

 multinucleated Opalinids of the Bufos: 5, That the Hylidae arose 

 comparatively late in the Antarctic continent and did not reach 

 tropical America until Patagonia united with tropical America: 

 That having reached the tropical forests of America the Hylids 

 found here conditions favorable for diversification and rapid increase 

 in numbers. [Further study of South American paleogeography in- 

 duces me now (1922) to suggest the origin of the Hylidae in the 

 southeastern Brazilian highlands when in the Cretaceous this region 

 was isolated as an island (see p. 364).] : 6, That the genus Proto- 

 opalina is the oldest of the four Opalinid genera and is found in all 

 parts of the world where climatic conditions are favorable, and has 



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