A FLIGHT OF PIGEONS. 



CHAPTEE XVI. 



THE PIGEONS AND SAND-GROUSE. 



Order COLUMB,E. 



THE pigeons form such a well-marked group that there is but 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 



