A FLIGHT OF PIGEONS. 
CHAPTER XVI. 
The Pigeons and Sand-Grouse. 
Order Columb^e. 
The pigeons form such a well-marked group that there is hut little difficulty in 
recognising any of their numerous representatives at a glance. In all, the moderately 
large head is set on a graceful neck, and the body is rather compact and stoutly 
built. Swollen at the extremity, the beak has its basal portion covered with a soft 
skin, in which open the nostrils. The legs are coated with hexagonal scales, and 
are usually more or less thickly feathered on the upper-part, although sometimes 
naked; the feet have four toes, the first of which is placed on the same level as 
the others. With the exception of the ground-doves, in which the wings are short 
and rounded, most of the living species have long, powerful quill-feathers, but the 
dodo and solitaire were incapable of flight. As regards osteological characters the 
pigeons have a cleft (schizognathous) palate, in which respect they and the sand- 
grouse differ from all the preceding groups; the upper bone of the wing or humerus 
is provided with a triangular deltoid crest, very similar to that of the sand-grouse, 
to which is attached the great pectoral muscle; thus rendering these birds capable 
of protracted and powerful flight. The majority of the pigeons are indeed excellent 
flyers, capable of traversing enormous distances in an incredibly short time ; as an 
