294 THE TRANSFORMATIONS OF THE ANIMAL WORLD 



I. MIGRATIONS OF PRIMARY TIMES. Towards the 

 end of Primary times, the geographical distribution 

 of certain genera of Stegocephalous Amphibians, 

 who inhabited the marshy lagoons of the Coal 

 and the Permian epoch, clearly points out to us 

 the easy communications established, on the one 

 hand, between Europe and North America, and, 

 on the other, between South Africa, India, and 

 Australia. 



In the group of small salamander-like forms called 

 Microsaurians, the Lepterpeton and Keraterpeton 

 genera are met with at once in the coal seams 

 of the Ohio, in those of Ireland, and in the 

 gas coal of the lower Permian of Nyram in 

 Bohemia. The genus Hylonomus of the Nova Sco- 

 tian Coal recurs in a hardly different form in the 

 lower Permian of Bohemia. A lacertiform type 

 of larger size, the Dendrerpeton, has been found, 

 as its name indicates, in the hollow tree trunks of 

 the coal forests of Nova Scotia and in the gas coal 

 .of Bohemia. A certain number of other European 

 genera possess, in North America, representative 

 forms so near to them that it is impossible to doubt 

 the easy geographical connections existing at that 

 epoch between the two worlds. 



In the same way, in the Southern Hemisphere, 

 from the sandstone of Karroo in South Africa, from 

 the strata of Gondwana, in the Indian Archipelago, 

 and, lastly, from the Triassic strata of Australia, 

 have been dug up several genera of Amphibians, 

 the Micropholis, the Bothriceps, and the Brachyops, 

 in part common to these three regions, between 

 which geographical connections doubtless estab- 



