148 (JALAPAGOS ARCIIIl'ELAGO. 



1. Geospiza masriirostris. 2. Geospi/a fortis. 



3. Geospizuparvula. 4 CtrthiJea ohvaoea 



being only one intei'mediate species, with a beak 

 of the size shown in Fig. 2, there are iio less than 

 six species with insensibly graduated beaks. The 

 beak of the sub-group Certhidea is shown in Fig. 

 4. The beak of Cactornis is somewhat like that 

 of a starling ; and that of the fourth sub-group, 

 Camarhynchus, is slightly parrot-shaped. Seeing 

 this gradation "Tind diversity of structure in one 

 small, intimately-related group of birds, one might 

 really fancy that, from an original paucity of birds 

 in this archipelago, one species had been taken and 

 modified for different ends. In a like manner, it 

 might be fancied that a bird originally a buzzard 

 had been induced here to undertake the office of 

 the carrion-feeding Polybori of the American con- 

 tinent. 



Of waders and water-birds I was able to got only 

 eleven kinds, and of these only three (including a 

 rail confined to the damp summits of the islands) 

 are new species. Considering the wandering hab- 

 its of the galls, I was surprised to find that the spe- 



