THE PIGEON. 201 



90, The scapula, a sabre-shaped bone, articulated 

 immovably to the corresponding coracoid, so as to make 

 with it a somewhat acute angle the coraco-scapular 

 angle, and passing backwards over the ribs : its proximal 

 or anterior end is expanded, and presents two facets for 

 articulation with the coracoid, and, externally, a large demi- 

 facet which completes the glenoid cavity. 



91. The furcula, or "merrythought," a V-shaped bone, 

 articulating by a facet on the outer surface of each of its 

 extremities with the facet already seen on the corresponding 

 coracoid, and passing backwards and downwards, its angle 

 being connected by ligament with the carina sterni. 



92. In the young bird, the furcula consists of separate paired bones, 

 the clavicles, with a small median ossification, the interclavicle. 



XIII. Note in the fore-limb : 



93. The general composition of the limb : it consists of a 

 proximal division, the brachium, containing a single bone, 

 the humerus ; a middle division,- the antibrachium, 

 containing two bones, a larger, the ulna, and a smaller, the 

 radius ; and a distal division, the manus. 



94. The position of the parts : in the position of rest the 

 three divisions are bent upon one another in the form of a 

 Z ; extended for flight, they are almost in the same straight 

 line : in the latter case the limb presents a dorsal and a 

 ventral surface, pre-axial or anterior, and post-axial 

 or posterior, borders ; the radius is then seen to be pre- 

 axial, and the ulna post-axial. In the position of rest, the 

 humerus extends backwards from its articulation with the 

 shoulder girdle, undergoing at the same time a slight 

 rotation, so that its dorsal surface looks inwards and 

 upwards, and its pre-axial border outwards and upwards; 

 the antibrachium has its dorsal surface directed outward 



