1886.] Relation of Pectoral Muscles of Birds to Power of Flight. 25 
in the genus Eutznia, where difference of locality has had such 
an effect on the coloration as to give rise to several species 
being made out of the common garter snake. 
I have procured these newts from many places in New York 
and New Jersey States and different parts of Long Island, of 
every shade of red up to very bright scarlet, yet within a radius 
of many miles from Brooklyn, where the wridescens and its vari- 
ety are both plentiful, I never find the latter other than a reddish- 
brown, varying from light to very dark. Sometimes late in 
December I find little brown ones with flame-colored spots, in 
the ponds. These are so greatly attenuated it is possible they 
have returned to the water in search of food, lacking on land, at 
so late a period when all animal life which would be available for 
them disappears from the surface. 
A+ 
THE RELATION OF THE PECTORAL MUSCLES OF 
BIRDS TO THE POWER OF FLIGHT. 
BY CHARLES L. EDWARDS. 
o all the modes of animal locomotion flight is the most rapid, 
the most graceful, the most fascinating. With one important 
exception this power separates the bird from the other verte- 
brates and gives it preëminence in motion. Its whole structure— 
the conical form of the body offering so little resistance to the 
air, the hollow bones, the air-sacs and the weaving together of 
the smallest barbules to form the close web of the wing—all 
denote that in the air, in flight, is the bird’s life. - 
While in a very general way much has been observed with 
regard to the variation in the power of flight of species differing 
quite widely from each other, yet there are still some unsolved 
problems connected with the highest form of motion. 
Before attempting the solution of any special problem there 
are certain mechanical elements of flight with which we must 
become familiar. 
A body much heavier than air is to be propelled with great 
speed through the air. The resistances are the force of gravity 
and the air itself. 
The perpendicular action of the. broadly expanded wings op- 
poses as much as possible the force of gravity, while the narrow 
