POSITIONS ASSUMED BY BIRDS IN FLIGHT—BEETHAM. 435 
In plate 1, figure 1, the gannet has not even risen to its feet prior 
to lifting the wings, but is sitting on the edge of the nest. The 
apparent leg supporting it on the near side is a delusion, for instead 
of being the metatarsus, as it seems, it is really the closed webbed 
toes hanging downward from the raised and hidden leg, only the 
claws really touching the nest. The reason for this peculiar position 
is the newly-hatched chick, hardly discernible, lying in the nest, 
which would inevitably have been crushed had the bird rested on its 
expanded foot. 
This raising of the wings preparatory to diving forth is perhaps 
more convincingly shown in figure 2, as the photograph is taken 
from a point on the same level as the bird, and shows the wings 
held up far above the bird’s head. This picture, as also figure 1, 
embraces another and more important point—that the unfolding or 
straightening of the wing takes place, if again there is no extreme 
haste, subsequent to the raising. This especially refers to the 
pinion. 
It will be noticed that although the humeri are raised almost to 
meeting above the back (pl. 1, fig. 2) the ulne are not fully extended 
and in line with them, while the pinions are little divergent from the 
latter, still making an acute angle with them. Casually one might 
have expected that, had there been any precedence, the pinion 
being the most important factor, would have been the first to assume 
the position requisite for flight, but if these two photographs be 
carefully examined the reverse appears to be the case. In short, it 
may be said that the unfolding of the units of the wing seems to be 
sequential, starting with the humerus, and not simultaneous. 
This is, I fear, directly at variance with the writings of many 
leading ornithologists and anatomists, and I can only put forward the 
photographs in support of my observations. Undoubtedly the 
arrangement and articulation of the wing-bones appear to indicate 
that the unfolding will take place mechanically throughout on any 
one part being extended, but laboratory theories, however much 
they may be upheld by inanimate evidence, can not pass unchallenged 
when they aré found to be in apparent contradiction to observation 
of the living action supported by corroborative photographs. 
In plate 2, figure 1 shows the bird at the very moment it is diving 
from the cliff, only the tips of its toes touching the rock, and it will be 
noticed, as intimated before, that the slope of the body is strongly 
upward. The wings have not even yet been fully straightened. 
This final unfolding and stiffening appears, so far as I can ascertain, 
to take place at the very moment of departure, and had this photo- 
graph been taken a minute fraction of a second later it would no 
