Knoeland.] 138 [March 15, 



considerable numbers, but never alighted on it, as the booby of the 

 Atlantic does. On account of the great length of their wings and 

 the shortness of their legs, they cannot rise, like the gulls, directly 

 from the water, but are obliged to run along the surface like the 

 smaller petrels, beating the water with their feet until sufficiently 

 elevated to use their wings. 



Flying- fish also appeared, but were neither so numerous nor so 

 large as in the Southern Atlantic. The ventrals were expanded 

 like the pectorals in the act of flight, the former being much the 

 smaller. They rose out of a perfectly smooth sea, showing that they 

 are not mere skippers from the top of one wave to another; they 

 could be seen to change their course, as well as to rise and fall, not 

 unfrequently touching the longer, lower lobe of the tail to the surface, 

 and again rising, as if they used the tail as a powerful spring. 

 While the ventrals may have acted chiefly as a parachute, it seemed 

 that the pectorals performed, by their almost imperceptible but rapid 

 vibrations, the function of true flight. " Another reason which leads 

 me to think they perform a true flight, is the way in which they reen- 

 ter the water. After reaching the end of their aerial course, they drop 

 into the water with a splash, instead of making a gradual and gentle 

 descent, like the flying-squirrel, flying-dragon, and other vertebrates 

 with membranes acting as parachutes. The drying of the flying 

 membrane in the air would prevent the small but numerous motions 

 necessary for true flight, and the animal therefore suddenly drops 

 when the membrane becomes stiff. I do not see how the drying of 

 the pectorals would affect their action as parachutes. 



At the same time were seen small Portuguese men-of-war (Physa- 

 lid) no larger than an olive, and without the purple reflections 

 of the larger ones, so often met with in the Atlantic. Whether these 

 were the young, or full-grown individuals, I do not know. I saw 

 none larger than these, and they were not numerous. 



As we approached the coast off the Gulf of California, the petrels 

 left us, and were replaced in an hour or two by white gulls, about 

 the size of Bonaparte's gull, but either entirely white, or with a very 

 slight lavender-blue tinge on the back and wings. These had an 

 entirely different way of alighting and rising from the water; they 

 did not push forward their feet to arrest their course, but circled 

 round like pigeons until their headway was stopped, then quietly 

 settled upon the water, immediately folding their wings. They also 



