212 Letters , Announcements , fyc. 
The Wings of Birds .—Professor Flower, F.R.S., Director of 
the British Museum of Natural History, gave a lecture on 
Friday, 19th February, at the Royal Institution, on the Wings 
of Birds. He said that the power of flying through the air 
was one of the chief characteristics of the class of birds. 
Although some members of the other great divisions of the 
Vertebrata possessed the power in a greater or less degree, 
they were exceptional forms, whereas in birds the faculty of 
flight was the rule, its absence the exception. He then 
pointed out the peculiar modifications of the fore limb of 
the bird which fitted it for his use as a flying-organ. In the 
vast majority of existing birds the wing was constructed 
upon the same essential type down to all the details of the 
number, arrangement, and structure of the feathers, and of 
their position in relation to the different bones constituting 
the skeleton of the wing, which were fully described and 
illustrated by diagrams. Minor modifications of this type 
resulted in organs so different in appearance and use as the 
powerful wings of the Albatross and Swift, which enable 
their possessors almost to live in the air, and those of the 
Great Auk and Dodo, too small and feeble to raise the body 
from the surface of the ground. A totally different type, so 
far as the arrangement and structure of the feathers are 
concerned, is seen in the fin-like wings of the Penguins—birds 
which, on this as well as on other grounds, ought to occupy 
a far more distinct position in the class than has hitherto 
been accorded to them. A third type of wing is that of 
the birds of the Ostrich group, in which the feathers are 
so imperfectly developed as to make them useless as organs of 
flight. The question which naturally presents itself with regard 
to these birds is whether they represent a stage through which 
all have passed before acquiring perfect wings, or whether they 
are descendants of birds which had once such wings, but which 
have become degraded by want of use. In the absence of 
paleontological evidence it is difficult to decide this point. 
The complete structure of the bony framework of the Ostrich's 
wing, with its two distinct claws, rather points to its direct 
descent from the reptilian hand, without ever having passed 
