298 



THOMAS DWIGHT ON 



where a foramen is found. The front arch is more or less fused with the skull. The 

 lateral masses at the places where the joints should be are completely fused. 



9638. — An old Eg3-ptian skull of the 12th dynasty, probably male, four thousand 

 years old, given nie by Dr. John Dane. On the right the posterior arch of the atlas 

 hardly projects from the level of tlie foramen magnum. On the left the arch is free but 

 imperfect, ending posteriorly in a projecting point. 



9639. — Base of a .skull, probably male and white, from the dissecting-room a few 

 years ago. It is almost the counterpart of the last, only the greater fusion of the atlas is 

 on the left and the free point on the right. 



8590 (Mason Warren Collection). — Probably white and female. Skull, with right 

 half of atlas fused, left half wanting. The right half of the atlas is tolerably well devel- 

 oped. The front part is practically perfect, but ends sharph- near the median hue with a 

 surface that apparently had been covered with fibro-cartilage. The posterior half is 

 less developed, and ends before reaching the median line as a thickening of the border 

 of the foramen magnum without any projecting point. The left half of the atlas evi- 

 dently had been distinct, and was lost. The occipital bone on that side is practically 

 normal with a rather low condyle. 



132. — Skull, with atlas fused at the places of the joints. In other parts the atlas is 

 well and symmetrically developed, and quite distinct. There is a hint of an old joint on 

 the left. Probaldy the fusion is a pathological occurrence during life. 



Fusion of Axis and the Third Vertebra. 



4767. — The two vertebrae sawn through near the median line. The place of union 

 of the bodies is very obscure on the front, but clear on section. The axis seems decidedly 



less long (vertically) than usual. The front \ie\v is nearly 

 symmetrical, except that the transverse processes and the costal 

 elements are nearer together on the left than on the right. 

 The intervertebral foramina, seen from within, are about equal. 

 While the laminae are quite fused, their duplicity is evident ; 

 and there are four tubercles at the end of the double spinous 

 process. The length of the axis from the top of the odontoid is 

 3.5 cm., the total length of the two vertebrae 5.3 cm. A very 

 curious feature, in view of an observation by Lebouccj, which is 

 considered later, is a linear fissure on the front of the right half of the specimen, which 

 at first sight suggests a repetition of the joint between the atlas and axis. It appears. 



4767. 



