470 



are more advanced in development; none of them being removable 

 except that of the fourth vertebra of the older animal. Although 

 these epiphyses are all joined to the centra by bone, the degree of 

 union is not uniform. The fusion of the fourth is least in amount. 

 In the third, fifth, and seventh it is more marked, and about equally 

 advanced. It should be noted that coalescence has apparently com- 

 menced laterally; or at any rate, has proceeded more rapidly at the 

 sides; for, though the epiphysial line can be detected quite readily 

 all round the vertel)ra, it is much the least obvious in the lateral 

 parts. 



The cephalic epiphysis of the sixth cervical vertebra stands apart 

 because of a closer union with its centrum than is possessed by any 

 other epiphysis of the cervical, thoracic or lumbar vertebrae. It is 

 apparent that complete formation of the vertebrae occurs earliest in 

 the atlas, lower cervical region, sacrum and the adjacent parts of 

 the tail. 



Thoracic vertebrae. It is conceivable that a small amount 

 of ossification is required to complete the tips of the spinous pro- 

 cesses, but no distinct epiphyses can be found. The transverse pro- 

 cesses are fully formed. The tips of the mammillary processes are 

 covered by a thin layer of cartilage, but there are no epiphyses. In 

 the twelfth vertebra in both skeletons the accessory processes present 

 an appearance which suggests that there has been a thin cap of bone 

 in the form of an epiphysis: its independence, however, has been lost, 

 and it would be necessary to examine a younger specimen in order 

 to be certain on this point. The accessory process of the thirteenth 

 (last) thoracic vertebra has an apex which is obviously incompletely 

 ossified. 



All the caudal epiphyses of the vertebral bodies were readily 

 separated during preparation. The same may be said of all the 

 cephalic epiphyses except those of the first and second vertebrae in 

 the older specimen, and of the first only in lion No. 2. In these 

 vertebrae the adherent part of the epiphysis is that portion of it which 

 enters into the formation of the derai-facet for the head of the rib, 

 i. e. as in the cervical region, the lateral part of the epiphysis is the 

 first to become bonily united to the centrum. 



There are no caudal demi-facets after the ninth vertebra; and in 

 lion No. 2 the left thirteenth vertebra lacks a cephalic demi-facet as 

 well, since the left last rib does not articulate with the spinal column. 

 In those thoracic vertebrae in which there are no caudal demi- 

 facets, the caudal epiphysis presents a feature which is of sufficient 



