484 



ME. 0. SALVIN ON THE AVIFAUNA 



adult. In this the crissum is nearly pure black, the feathers being very narrowly edged 

 with white. The bill, as pointed out by Mr. Gould, has a distinct tooth-like prominence 

 in the middle of the cutting-edge of the mandible on either side. The female is darker 

 than is usual in other Geospizm. 



Of G. dentirostris Dr. Habel says: — " Usually seen in groups of families, frequenting 

 low bushes in search of fruit, the members uttering a cheerful chirping note. In the 

 morning they visit the bushes growing near the shore ; later in the day they retire more 

 inland. I only met with this bird on Abingdon Island, where it predominates over 

 the other species in numbers." — II. 



Before passing to the next genus I will recapitulate the measurements of all the 

 above species of Geospiza, except G. nehulosa and G. dubia, of which oui- knowledge is 

 as yet incomplete, and also G. dentirostris, which seems to have distinct characters of 

 its own. 



G. fortis. 

 inches. 

 2-95-2'5 

 1-85-1-5 

 0-90-0-8 



Of all except G. magnirostris the largest and smallest measurements are given. 

 From this table it will be at once seen that the gradations from the largest to the 

 smallest species are quite complete, and that the only grounds for separating them at 

 all rests upon the dimensions of the bill, where the steps are not quite so gradual. 

 But the dimensions of the bills furnish but slender specific characters, as will be seen 

 by the accompanying cut. 



6. magnirostris. 



G. strenua. 



G. strenua. 



G. fori i I 



G. fortis. G. fuliginosa. G. fuliginosa. G. parvuh. G. parvula. 



The important and indisputable fact remains that whether we treat Geospiza as 

 including one highly variable species, or as comprising several in themselves variable 



