244 



(each side) is composed of premaxilla, small maxilla, jugal, 

 and quadrate- jugal. The palatines (with a rudimentary 

 vomer between) are connected in front with the premaxillae 

 and maxillae, and behind with the basisphenoidal rostrum 

 and the two rod-like pterygoids (obliquely placed, and 

 articulating behind with the quadrates). The stout 

 triradiate quadrate* (the suspensorium), which forms the 

 articular surface for the lower jaw, is articulated with the 

 squamosal, the quadrate- jugal and the pterygoid. Each 

 ramus of the mandible or lower jaw consists of five bones 

 (dentary, splenial, angular, supra-angular and articular*). 

 In the floor of the mouth is the hyoid. 



( The bones marked * are substitution or replacement bones.) 



Give Short Descriptions of (I) the Pectoral Girdle and Fore- 

 limb, and (2) the Pelvic Girdle and Hind-limb of the 

 Pigeon. 



(1) See shoulder girdle, page 241. The front end of the 

 scapula is firmly attached to the upper end of the coracoid. 

 These ends conjointly form, on their outer sides, the glenoid 

 cavity. Above this cavity the coracoid end is produced 

 as a strong process curving inwards ; and to it the upper 

 end of the clavicle is attached. The end of the scapula 

 has a corresponding process ; thus the ends of the three 

 bones form an archway, the foramen triosseum. 



The parts of the fore-limb (wing) are upper arm, fore-arm, 

 wrist and hand or manus. The upper arm has one bone, 

 the humerus (with prominent head and deltoid ridge). The 

 fore-arm has two parallel bones, the slender radius and the 

 stouter ulna. The ulna is slightly curved, has a small 

 olecranon process at its proximal end, and bears the marks 

 of the secondaries. The wrist is represented by the two 

 proximal carpals (radiale and ulnare). The three distal 

 carpals are fused with the three metacarpals to form the 

 carpo-metacarpus, which is a stout bone (2nd metacarpal) 

 bearing a proximal knob (1st metacarpal) and united at 

 the ends with a parallel thin bone (3rd metacarpal). The 

 metacarpals bear three digits ; the first (thumb) and third 

 digits are small, the second has three phalanges. 



(2) See pelvis, page 241. At the junction of the ischium 

 and pubis with the ilium is the incompletely ossified socket 

 or acetabulum, for the head of the short femur or thigh 

 bone. The lower leg has a stout tibia with a splint-like 

 fibula ; the two proximal tarsals (ankle bones) are fused 

 to the distal end of the tibia, the whole forming the tibio- 



