329 



Class I. Group A. 4 spines showing the gradations between 

 11 and 13 pairs of ribs, the irregularity being at the junction of the 

 back and loins. This group might have been increased indefinitely. 



Group B. 5 spines all with cervical ribs of no great size. In 

 one the 1st thoracic rib is bicipital through fusion with a cervical rib. 



There is a general tendency in this group for an underdevelop- 

 ment of the last ribs to accompany the over development of the costal 

 elements of the 7th vertebra. Hence the thorax appears to be moving 

 towards the head on one or both sides. In one spine the last pair 

 of ribs look like transverse processes cut through at their bases. 



Class II consists of 8 spines in which there is more or less of 

 an approach to 25 perfect praesacral vertebrae. In the first the 25th 

 is almost a sacral vertebra; in the last it is almost a lumbar one. 

 They are arranged to mark the progression as regularly as may be. 

 In every case the 26th is the fulcralis, and there is always more or 

 less of a disc between it and the 25th, though they join by the lateral 

 masses. One of these spines is from a child of ten years, the only 

 non-adult spine in the collection. One presents fusion of the atlas 

 and occiput. One with 13 ribs has the last rib much smaller and 

 less rib-like on the same side with the greater sacralization of the 25th. 



Class III. Group A. 7 spines with the extra praesacral in 

 the thorax. One of them has a rudimentary 1st rib on one side. 



Group B consists of 3 spines with the extra vertebra in the 

 loins. In both of these groups the 26th is the fulcralis. 



Group C comprises only 2 spines, both ligamentous preparations 

 in which the 27th vertebra is the fulcralis: which consequently 

 have 2 additional praesacral vertebrae. In both the 26th 

 is sacralized on one side, but it very certainly is not the fulcralis. 

 One of these is the only spine in this collection that I did not find 

 myself. It has been in the Museum since 1847. It is that of an 

 adult probably passed middle age. It is very pathological. Not only 

 is there a marked skoliosis, but the laminae of the cervical vertebrae 

 are very much distorted and confused, several mingling together with 

 their neighbours of the same side and not being opposite to their 

 fellows. The first three right ribs moreover are fused. The sternum 

 is unfortunately wanting. The other spine, that of an old man, v\^as 

 taken in the season of 1899—1900. It is somewhat pathological owing 

 to bony growths connecting the bodies of the vertebrae which, I think, 

 undoubtedly occurred late in life. The axis is fused with the 3rd 

 vertebra. There is no disc between them. This might have disap- 

 peared from pathological causes, but the laminae are so fused that it 



