CucULIDJE.] OSTEOLOGIA AVIUM. [Centropim. 



from the cotyloid cavity to the caudal vertebrae, where it projects on each side of the first, 

 and is slightly turned upwards ; ischium broad, consisting of a triangular plate on each 

 side; the posterior margin nearly straight, projecting slightly backwards at its inferior 

 angle. Os pubis posteriorly to the cotyloid cavity consisting of a narrow strip of bone 

 projecting very slightly beyond the posterior angle of the ischium, to which it is anchy- 

 losed for nearly its whole length, the obturator foramen being represented merely J>y a 

 small oval foramen near its extremity, and a small rounded one behind the cotyloid 

 cavity. The anterior extremity of the os pubis is prolonged beyond the cotyloid cavity 

 In the form of a flattened blunt spine projecting forwards and downwards. 



Bibs of moderate size, narrow at their sternal extremities, and gradually widened to 

 their junction with the vertebrae ; styliform appendage rather long. 



Wing-bones short ; the posterior metacarpal bone much arched and perpendicularly 

 flattened. 



Leg-bones rather long ; the femur rounded, bent downwards, long in proportion to the 

 tibia; metatarsus and femur nearly equal in length. Metatarsus flattened in front, with 

 a shallow excavation at its distal extremity ; two indentations just above the trochlea 

 mark the divisions of the three bones composing it ; posteriorly rounded at its distal 

 extremity, flattened at its proximal, with a slight central keel extending downwards for 

 about half its length from the calcaneal process, which is rather prominent and blunt at 

 its extremity. 



Vertebral column strong ; the penultimate vertebra and the two next with a dorsal 



process. 



Measurements. 



Tenths. 



Length of humerus 26 



Length of ulna 22 



Length of metacarpus . . . . . 12 



Length of femur 24 



Length of tibia .34 



Length of metatarsus 22 



Length of sternum 18 



Tenths. 

 Breadth of posterior margin of sternum 14 

 Breadth of anterior margin of sternum 11 

 Depth of keel ........ o£ 



Length of head 30 



Breadth of head 11 



Length of pelvis . 20 



Breadth of pelvis 15 



Illustrations. 



Skeleton, Plate I. E. I Palatine bones, sternum, pelvis, and meta- 



tarsi, Plate XIII. fig. 1. 



Crotophaga, Linn. 

 Ani, Linn. 

 Cranium similar to Centropus, but rather natter on the vertex. 



Sternum rather shorter in proportion to its width. Remaining bones similar. The 

 anterior end of the os pubis slightly projecting. 



89 



