Vol XX 



1903 



I Snodgrass, Geospi'za, Cocoriiis^ and Ccrtltidia. 4^9 



mandible. The temporal crest is nearly obsolete, and the tem- 

 poral area below it is less extensive than in G. f. parviila. The 

 interorbital septum is so thin that it is almost membranous. 

 The angulation of the culmen is inconspicuous. The deflexure of 

 the upper tomium is about 48°. 



The shape of the nostril changes serially in the four skulls 

 described. In G. strenua the nostril is almost an isosceles triangle 

 with the base on a line with the upper edge of the zygoma. In 

 the smaller-billed species, however, the upper angle becomes 

 moved successively farther back, and the angle that the descend- 

 ing process of the nasal forms with the zygoma, which is almost 

 90° in G. strenua, slightly decreases. In G. f. aciitirostris the 

 upper angle of the nostril lies behind the vertical from the pos- 

 terior basal angle. 



The lower mandible is very slender and there is almost no 

 coronoid process. 



Geospiza scatidens fatigata (Ridgway). (Plate XVII, Figs. 16, 

 17, and 18.) — The Geospiza group, characterized by a long slender 

 bill, includes a number of forms that were once regarded as con- 

 stituting a separate genus called Cactornis. The supposed spe- 

 cies were separated on characters that have since been found to 

 intergrade in such a manner that they can better be regarded as 

 varieties of one species of Geospiza. Of this group, which has 

 been reduced to the species G. scandens, the subspecies G. s. 

 fatigata may be taken as typical. 



There is far less difference between the skulls of G. scandens and 

 G. fuligi?iosa than there is between the skulls of the latter species 

 and G. strenua. That is, the former genus Cactornis did not differ 

 in cranial structure from the simpler forms of Geospiza nearly 

 as much as did the species in this genus, as at first limited, differ 

 from one another. 



The temporal and lambdoidal crests are almost identical with 

 those of G.fuliginosa. The tip of the postfrontal process lies but 

 slightly before the tip of the squamosal process. The fronto-nasal 

 suture is deeply concave. It is more concave than in G.f. acutiros- 

 fris, in the latter species more so again than in G.fortis, while in G. 

 strenua It is almost straight. The angle of the descending proc- 

 ess of the nasal with the zygoma is still less than in G.f. acutirostris, 



