Birds. 9287 
The specimen of G. Crex from which the above measurements 
were taken was rather over eleven inches in length, and was therefore 
unusually large, and more than half as long agam as my specimen of 
G. pusilla, which measures exactly seven inches. Yet the foot of the 
smaller bird is of quite as great a spread as that of the larger bird, 
with the exception of the middle toe, and in the greater length of this 
toe G. Crex exceeds that of G. pusilla by only the sixteenth of an _ 
inch, which advantage is nearly balanced by the inner toe of G. pu- 
silla actually measuring slightly more than the same toe in G. Crex. 
In all members of the family Rallide we find a body more or less 
compressed or flattened on the sides, as though the bird had been 
forcibly squeezed between the two hands. 
This peculiar formation is designed to enable the bird to run with 
comparative ease between the stems of grasses and marshy plants, 
amongst which it hides and feeds, without checking its speed on the 
one hand, or causing such a disturbance of the covert on the other 
hand as to reveal its whereabouts. 
We also find the body deep from above downwards, and as a con- 
sequence in the skeleton we find a corresponding deep keel to the 
sternum. This is always the case in birds whose power of flight is 
considerable. The rails are for the most part migratory birds, being 
spread over an extensive geographical range, and only visiting these 
shores at certain seasons of the year. Their powers of flight must there- 
fore of necessity be highly developed, and thus we find on dissection 
of their bodies that the muscles called {into action during flight are 
largely developed; and the keel of the sternum, to which the muscles 
are principally attached, is proportionally deeper, stronger and rougher 
in its ridges than in many other birds of equal size. 
The keel is apparently set very far back on the sternum, but this ap- 
pearance is in reality due to the unusual length of the coracoid bones 
and clavicles, which, projecting forwards and downwards from the ster- 
num in a very slightly curved line, give the anterior third of the bird’s 
body a cone-like form. This peculiar formation, together with its flat- 
tened sides, enables the bird more readily to glide, serpent-like, with 
speed and silence, through its grassy and often tangled habitat. It is 
curious to observe how, in spite of its considerable powers of flight, the 
rail rarely, if ever, depends so much upon its wings as on its legs for 
a means of escape from danger. Its furtive habits, its keen senses of 
sight and hearing, its colour (so perfectly corresponding to the hues of 
those plants and sedges amongst which it dwells), lend to instinct a 
sense of security, independent of flight, which induces the bird, on 
