OCR Text |
Show physes again succeed from the 11th vertebra and are continued backwards to the thoracic. The cervical vertebrae are 12 in number. There are tnee cervico-thoracic; that is to say, there are three vertebrae beaung free cervical ribs. The 1st pair are reduced to the merest vestiges , the 2nd pair are long, bear vestigial uncinates, but no sternal segment; the 3rd pair bear large uncinates and a long styliform sternal segment, which does not, however, reach the sternum. Thus, it is obvious that, at no distant date, these three vertebrae formed part of the thoracic series and articulated witli^ the sternum. They differ, moreover, in form from the true cervicals, and resemble the thoracic series in having broad outstanding diapophyses. The cervical and cervico-thoracics of the Eurylaemidae differ conspicuously from those of the Menuridae and of the Coracii-formes, and resemble rather those of the higher Passeres. The thoracic vertebrae, six in number, have moderately developed, quadrangular, neural spines. Only the 1st thoracic bears a small hypapophysis. The centra are pierced by pneumatic foramina. The last thoracic has been incorporated with the synsacrum. Twelve vertebrae enter into the composition of the synsacrum in Calyptomena and Cymbirhynchus; 13 in Corydon. The numerical differences are as follows :- Calyptomena. Cymbirhynchus. Corydon. 44 MR. W. P. PYCRAFT ON THE [May 2, Thoracic..........1 1 Lumbar ..........2 2 3 Lumbo-sacral 3 2 2 Sacral ..............2 2 2 Caudal..............4 + 8 free caudal 5 + 8 free caud. 5 + 8freecaud. Total ........... 12 + 8 ,, 12 + 8 ,, 13 + 8 ,, Thus Calyptomena appears to have lost 1 post-sacral and Cymbirhynchus 1 pre-sacral. Corydon would appear to express the primitive number of these segments. The 2nd lumbar in Calyptomena bears a large pair of ventri-lateral processes abutting against the pre-ilia. The 1st sacral vertebra lies immediately caudad of the hinder margin of the acetabulum. The dorsi-lateral processes of the sacral and caudal vertebrae are long, and, by the ossification of the tendinous tissue overlying them, form a broad bony plate dividing the innominates. There are 8 free caudals, including the pygostyle. The diapophyses of those immediately following the synsacral series are not embraced by the innominate, owing to the fact that these are kept apart by the outstanding dorsi-lateral processes of the synsacral series. Corydon and Cymbirhynchus differ from Calyptomena chiefly in that the dorsi-lateral processes of the sacral and post-sacral |