CH. XV] ENDEMISM AND DISTRIBUTION: SPECIES 161 



of more and more localised species scattered about within or 

 close to their range, and (2) that there are many species of 

 local range, usually more or less overlapping one another, and 

 themselves overlapped in many places by fewer species of 

 rather wider range, and in the total occupying considerable 

 areas, which are as continuous as intrusions of the sea and 

 other barriers will allow, seem to cover the case of the bulk of 

 existing genera. The latter case also makes, though not so 

 strikingly, a hollow curve, for there are more species of small 

 areas. 



It is clear that the types of distribution shown by endemic 

 species, whether of endemic genera or not, are the same types 

 that one may see in the dispersal of genera, species, and varieties 

 of wider range; there is no place at which one can draw a line, 

 and say that here is the distinction between endemic and non- 

 endemic species. 



But the resemblances between endemic and non-endemic 

 species may be carried much further. In the case of the former, 

 as Ave have seen above, their usual grouping in a country shows 

 a few in the class containing those of widest local dispersal, and 

 larger and larger numbers as one goes down the scale to the more 

 localised classes. And this grouping shows, not only for the 

 grand total, but for the individual families and larger genera. 

 The actual figures for New Zealand show that the curve so pro- 

 duced is a hollow one (fig. on p. 162, curve 5). The peak in 

 the middle of the curve is accounted for, perhaps, by the opening 

 of Cook's Strait having checked the dispersal of some of the 

 species (127, p. 455). If, dipping at random into the New 

 Zealand flora, one take the Boraginaceae, and divide the en- 

 demics into five classes, one finds 2/1 (two in class 1), 1/2, 2/3, 

 5/4, 13/5; or if one take Olearia, one finds 2/1, 5/2, 4/3, 6/4, 14/5. 

 Always the same type of curve is formed, with an accumulation 

 of species at one end. 



But this same phenomenon shows in the case of all other 

 species, whether endemic or not. In Doona in Ceylon, for ex- 

 ample, one finds one species of large area, three of smaller, and 

 seven of areas smaller yet. With the largest endemic genus in 

 the Hawaiian Islands, Cyanea, one finds (ef. Cyrtandra above) 

 one species on four islands, six on two, and 21 on a single island. 

 Pelea, the next largest genus, shows 1/8 (one species on all 

 islands), 3/4, 3/3, 2/2, 11/1, again a hollow curve, running out 

 very much at one end. If one add up all the species of the 



W.A. 11 



