2 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 8l 



recent immigrants from the north. The place of the true frogs in 

 these southern lands is taken by the Leptodactylidae, a dominant group 

 which we might call the " southern frogs." This family is found in 

 South xA.merica, Central America, the Antilles and along the southern 

 coast of North America (many American genera and species) ; in 

 Tasmania, Australia, Papua and adjacent islands, the Xew Hebrides 

 Islands,^ and the Bismarck Archipelago (numerous Australasian 

 genera and species) ; also in South Africa (one genus, three species). 

 This remarkable distribution, in widely separated Southern Hemi- 

 sphere lands, has caused much discussion. IMost zoogeographers have 

 seen in this dispersal evidence of a southern land connection between 

 Australia and South America. The discovery of southern frogs in 

 Africa was so recent that the African occurrence has l)een but little 

 discussed." Some students, though fewer recently than formerly, 

 have vigorously disputed any such intercontinental connection, claim- 

 ing either that the American southern frogs are not close relatives of 

 those in Australasia (Gadow's earlier opinion, Eigenmann's later 

 view), or that the southern frogs originally belonged in the whole 

 Northern Hemisphere and that the South American and Australian 

 representatives all came from the old common northern stock, and 

 that more recently the northern members of the family have become 

 extinct (^latthew 1915, Noble 1922, Dunn 1923). This seems a most 

 unlikely suggestion in view of present knowledge. To be sure, the 

 origin of the mammalia seems to have been in the northern land mass. 

 The occurrence of mammals to-day in southern lands is due in con- 

 siderable part to their having spread southward in the past, although 

 some groups of major importance have evolved in the south, and one 

 other, the marsupials, seem to have used east-west dispersal routes 

 in both the Northern and the Southern Hemispheres. It is one of the 

 leading mammalian paleontologists, Matthew, who has recently most 

 ^^gorouslv upheld this hypothesis of northern origin and southward 

 dispersal and who has most extensively developed it. He has extended 

 it even to the point of claiming the probable northern origin of all [ ?] 

 groups of terrestrial animals [and plants ?] which arose during the 

 Tertiary and probably also the Mesozoic periods, holding that the 

 present Southern Hemisphere representatives of these groups are 

 archaic forms crowded out from northern lands by the competition 



^ One report only, and this very doubtful, apparently erroneous. 



" I shall describe soon a Protoopaliua parasitic in the South African lep- 

 todactylid Heleophryne, and discuss the significance of the presence of these 

 forms in South Africa. 



