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, 



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 Sciences, 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. But I have not at present sufficient material from the 

 Atlantic Coast to determine this satisfactorily. 



