278 



CALIFORNIA ACADEMY OF SCIENCES. 



being caught, they invariably vomited and purged a reddish, 

 thin, oily fluid of an extremely strong odor. The single 

 egg which they lay is held against the abdomen of the sit- 

 ting bird. It is shaped much like a pigeon's egg, white in 

 in color, while one end is wreathed with a fine spattering of 

 minute dots of reddish brown and pale lavender. 



The average measurements of fifty eggs taken March 4th 

 and 5th, is 35.7 x 27 mm. The largest eggs measure 37.5 

 X 27.5; 38x27.5; 37 x 28 mm., and the smallest 31.5 x 26; 

 32.5x25,5; ; 33 x 27 mm. 



DIMENSIONS OF SPECIMENS. 



Collector' 

 No. 



2555 

 2556 

 2558 

 2559 

 2560 

 2561 

 2563 

 2561 

 2566 

 2567 

 2568 

 2557 

 2562 

 2565 



Sex and 

 age. 



ad. 

 ad. 

 ad. 

 ad. 

 ad. 

 ad. 

 ad. 

 ad. 

 ad. 

 ad. 

 ad. 

 ad. 

 ad. 

 ad. 



Wing. 



mm. 

 155 

 162 

 158 

 161 

 162 

 160 

 166 

 168 

 162 

 i66 

 160 

 171 

 167 

 159 



Middle 



toe and 



claw. 



mm. 



29 



29 



28 



28 



28 



28 



29.5 



30 



29 



30 



28 



28 



29 



30 



No. 11,164 in the collection of the Cal. Academy of Sciences, from At- 

 lantic Ocean, measures— Tail, 94 mm.; depth of fork, 18 mm.; culmen, 16 

 mm.; tarsus, 22.5 mm.; middle toe and claw, 24.5 mm. 



No. 11,165 in the collection of the Cal. Academy of S-iences, from At- 

 lantic Ocean, measures — Tail, 92 mm.; depth of fork, 18 mm.; culmen, 16 

 mm.; tarsus, 22 mm.; middle toe and claw, 25 mm. 



There is indicated in the longer tail, greater depth of fork and longer 

 middle toe which is constant in the Guadalupe example, a Pacific or at least 

 a Guadalupe Island form of Oceanodroma, differing mainly in these respects 

 from 0. leucorhoa. Bat I have not at present sufficient material from the 

 Atlantic Coast to determine this satisfactorily. 



