331 



might be included in the next group but which is separated on account of 

 its rarity. The number is H-3. It is from an old insane woman. The 

 formula is C. 6, T. 12, L. 6, S. 6, C. 4. The last lumbar is sacralized 

 on one side. There are only six cervical vertebrae, and of these the 

 atlas and axis are fused. The odontoid, the anterior arch of the atlas, 

 and its lateral masses are all indistinguishable, being fused into one 

 piece. A projection 8 mm long extends above the rest, presumably 

 from the odontoid. The posterior arch of the atlas is well developed 

 and shows the groove for the vertebral artery behind the articular 

 facet, which is nearly plane. The 6th vertebra would pass for a 7th, 

 and the 7th for a 1st thoracic. The latter has a pair of ribs of which 

 the right one is a normal 1st rib to all appearance, but in the ab- 

 sence of the sternum its termination is unknown. The left one has 

 a well-formed head, neck and tubercle, with a small shaft which ends 

 7 cm in a straight line from the tubercle. The termination is free 

 and rounded. It is almost a typical rudimentary 1st rib. The 12th 

 pair of ribs are long for the size of the thorax. The 6th lumbar 

 vertebra is sacralized on the left. It would seem as if the thorax 

 had moved a step upward. 



Group D consists of 6 spines with partial sacralization of the 

 24th vertebra. They are arranged in the inverse order of those in 

 Class II. That is they are arranged to show the gradations of in- 

 creasing sacralization of the 24th. In some of them the process had 

 gone so far that I was strongly inclined to call the 24th the ful- 

 cralis, but I pursued the more conservative course. 



Class V comprises three groups in all of which the 24th is the 

 fulcralis. While I believe this statement to be true, I must admit 

 that in some cases it might be difficult to convince an adversary. In 

 other cases there can be no possible question of the fact. G r o u p A 

 comprises 3 spines in which the praesacral vertebra that is wanting 

 is absent in the loins. Group B contains 2 spines in which it is 

 wanting in the back. One of these, 478, is a very important one. 

 It came from a negro. Although there are only 23 praesacral 

 vertebrae, the lower end of the thoracic region and the lumbar region 

 are very nearly typical. The 24th vertebra is evidently the fulcralis. 

 Group C contains 2 spines both of great rarity. They may be de- 

 scribed as having a praesacral too few and at the same time a cervical 

 rib of remarkable development, or as having a cervical vertebra too 

 few. I have adopted the former method. I described the first of 

 these, 267, in the Journ. of Anat. and Physiol., Vol. 21. The formula 

 is C. 7, T. 11, L. 5, S. 5, C. 4. There is on the left a moderately 



