AXIAL SKELETON OF THE OSTEICH. 



439 



There is a small pneumatic foramen in the vertebral margin near the head of the rib. 

 The dorsal (or more postaxial) margin of the rib is rather shorter than the ventral 

 one, owing to the head and neck being slightly longer than the tubercle. 



THE VERTEBRAL RIBS OE RIGHT SIDE (size of figures I-X, | natural size : figures IV', V, VII', 



i natural size). 

 Fig. 7.5. 



I. first rib : its preasial margin is between h and ( ; its vertebral margin extends downwards from t to the apex 

 of its ventral margin. II. second rib. III. third rib. IV. fourth rib ; IV'. proximal end of fourth rib, 

 showing the pneumatic foramem (/), the cup-Kke surface for the diapophysis (t), and the convex tubercle 

 (7i) for the parapophysis. V. fifth rib ; V. its proximal end (the small but sharp prominence near the 

 letter / is produced by the ridge which passes outside the root of the capitulum). VI. sixth rib. VII. 

 seventh rib ; VII'. its proximal end, showing the great articular surface for the diapophysis and 

 the very large pneumatic foramen. VIII. eighth rib, showing the small opening or defect of ossification 

 on the tuberculum, near its junction with the capitulum. IX. ninth rib, showing a defect of ossification 

 larger than that in the eighth rib. X. tenth rib, with a defect of ossification relatively yet larger. In all 

 the figures, h denotes the capitulum, and t the tuberculum ; «, the uncinate process. 



The Second Bib. ' 



This still absolutely small rib (fig. 75, ii) is relatively much elongated compared with 

 the first rib, its length being about three times its greatest breadth, and three times the 



