ORNITHOLOGY OF GUADALUPE ISLAND. 311 



lowing measurements in millimeters: 19 x 14; 19 x 14; 

 19.5 xU.5; 19.5 x 14.5; 19.5 x 15. 



The average size ascertained from a series of fifty-five 

 eggs, is 19 X 14 mm. 



The two largest eggs measured 21 x 15 mm. and 20 x 16 

 mm. respective!}' ; the two smallest, 17 x 14 mm. 



Two different stages of the young plumage w^ere taken, 

 descriptions of which are here given : 



Ch. — Young. Above similar to adult but "niuch darker, 

 especially the head and neck, Avhich lack the speckled mark- 

 ings. Wings and tail as in adult but darker, the bars 

 across middle tail-feathers dull black. The outer half of the 

 pale cinnamon on end of tail-feather finely mottled with 

 dusky. Under parts pale pinkish cinnamon; the entire 

 throat obscured with a faint dusky suffusion. Crissum 

 darker than abdomen and unmarked. 



Wing, 67 mm.; tail feathers, 53 mm.; bill from nostril, 12 

 mm.; tarsus, 19 mm.; middle toe, 13 mm. 



(No. 2530 — Imm iture, author's collection. Guadalupe 

 Island, February 19, 1886.) 



First Plumage. — Above lighter than the immature speci- 

 men and grayer than the adult plumage. Below, including 

 throat, pale sulphurous white, becoming pinkish on sides, 

 and crissum, which is unmarked. 



Wing, 57 mm.; tail feather, 34 mm.; bill from nostril, 8.5 

 mm.; tarsus, 20.5 mm.; middle toe, 14 mm. 



(No. 2125 — Nestling, author's collection. Guadalupe 

 Island, January 23, 1886. ) 



By the table of measurements it will be seen that the bills 

 of specimens (collected eleven years after the species was 

 discovered) average about 15.5 mm.; while those taken in 

 1875 I find to average fully a millimeter less. A decade 

 hence it will be interesting to know whether this increasing 

 development has still continued. 



