CH. XV] ENDEMISM AND DISTRIBUTION: SPECIES 153 



west Ceylon) is occupied by one of its species, D. zeylanica, while 

 the others occupy smaller and smaller areas within this, down 

 to a comparatively few square miles. This is perhaps the most 

 common type of distribution with genera of small area, which 

 upon the theory of Age and Area are to be regarded as young 

 beginners. Another instance is Haastia in New Zealand (fin-, on 

 p. 154). 



Distribution of the same type, but more extended, is shown 

 by the (chiefly endemic) species of Ranunculm in New Zealand 

 (fig. on p. 156), and by very many other genera in that coun- 

 try. In this map the widely distributed species, i.e. those occur- 

 ring outside of New Zealand, are shown bv dotted lines, and it 



DOONA, 



will be noticed that three of them range all over New Zealand 

 (including the little Stewart Island to the south), and also to the 

 Chathams, 375 miles to the eastward, while the fourth only 

 ranges from the far south up to the middle of North Island. The 

 endemics all have ranges within that of the first three wides, 

 among which probably, upon the general implications of Age 

 and Area, one must prineipally look for their parent or parents. 

 The endemic with the greatest range covers slightl}' more ground 

 than the wide of least range, and the others occupy smaller and 

 smaller areas, becoming steadily more numerous in going south, 

 till a maximum is reached a little south of the middle of South 

 Island, as indicated in the following figures (cf. p. 77), which 



