104 



MEEJSTIC VARIATION. 



[part I. 



pair of ribs. The appearance of the next vertebra is shewn in the 

 figure (Fig. 10, I.). Anteriorly, and as far as the level of the 

 posterior surface of the transverse processes, it is normal, save that 

 its neural spine is rather small from before backwards. The trans- 

 verse processes bear a pair of normal ribs. But behind this pair 

 of transverse processes the parts, so to speak, begin again, rising 

 again into a neural spine, and growing outwards into a second pair 

 of transverse processes, with a second pair of normal ribs. Poste- 

 riorly again the parts are normal. This specimen is described 

 in the Catalogue of 1S53, as " 148th and 149th vertebras anky- 

 losed," but upon a little reflexion it will be seen that this account 

 misses the essential point. For the bone is not two vertebras 

 simply joined together as bones may be after inflammation or the 

 like, but it is two vertebras whose adjacent parts are not formed, 



a 



Fig. 10. Two examples of imperfect division of vertebras in one specimen of 

 Python tigri*. I. The vertebras 147 — 150 seen from the right side, shewing the 

 imperfect division between the 148th and 149th. The condition on the left side is 

 the same. II. View of dorsal surface of vertebras 165 — 167, shewing duplicity of 

 166th vertebra on the right side. On this side it bears two ribs. The left side is 

 normal. (From a skeleton, in Coll. Surg. Mus., No. 602.) 



