261 



The anterior limb of the transverse process of this cervical vertebra 

 is a rib element and represents the proximal part of the rib fused 

 with the vertebra. In many cases, however, its morphology is appa- 

 rent, although it is as yet too rudimentary to deserve the name of 

 cervical rib. Two such varieties are shown in Figs. I and II. In the 

 former of these the rib element is fused at the tuberculo-transverse 

 articulation only, while the head of the rib remains free. In the 

 second of the two a small portion of the shaft is also present beyond 

 the tuberculo-transverse fusion. This latter variation was found to be 

 associated with an unusually large costal arch formed by the first 

 dorsal rib and in it the nerves were directed more forwards than 

 outwards. In the normal specimens the nerves pursue a more or less 

 transverse course in the neck and thus the shaft of the cervical rib 

 is rarely represented in these very rudimentary specimens. 



Fis. I. 



Male. 



Fig. II. 

 Age 18 — 20. 



Nubian series. 



Fig. I. Seventh cervical vertebra. 

 No. 89, Ptol. 'h Nat. size. 



Exhibits an early stage in the development of a cervical rib. On the left side 

 the vertebra is normally formed. On the right side the rib present comprises the 

 head, neck, and tubercle only. The tubercle is fused with the transverse process 

 while the head is free. 



Fig. 11. Seventh cervical vertebra. Adult. Female. Nubian series. No. 2/520. 

 'I' Nat. size. 



This specimen illustrates another type in the early development of a cervical 

 rib. On each side both head and tubercle of the rib are fused with the vertebra. 

 A small portion of the shaft of the rib is also present on each side. 



The next illustration (Fig. Ill) shows a rudimentary cervical rib 

 in which still more of the shaft is represented and tbe element becomes 

 dissociated from the vertebral column to constitute a separate bone. 

 Two instances of this type occur in the present series. The disposition 

 of the soft parts in these specimens and at this particular situation 

 approximated to that of the thorax more than to that of the neck. 



