REPORT ON THE BONES OF THE HUMAN SKELETON. 
69 
and in two the anterior diameter was greater than the posterior. The body of the 5th 
himbar was deeper in front than behind in all the five complete skeletons, the maximum 
difference between the two surfaces being 3 mm. 
When these dimensions are compared with those obtained from the European spinal 
columns, it will be seen that in the 1st, 2nd, and 3rd lumbars the body was more 
constantly deeper behind than in front in the Australians than in the Europeans. In 
the 4th lumbar, whilst it was the exception in the Europeans for the body to be deeper 
behind than in front, in the Australians one-half the skeletons exhibited this relation. 
In all the Australians, as in the Europeans, the body of the 5th lumbar was deeper in 
front than behind ; the mean vertical diameter of the anterior surfaces was 23 "2, and of 
the posterior 21 '2, a difference of 2 mm. only in favour of the anterior surface ; whilst in 
the Europeans the anterior surface was on the average 4*6 mm. thicker than the posterior. 
In Table X. the mean index of the five Australian skeletons in which the lumbar spine 
was complete is given. The mean index of the separate vertebrsB diminished from 114*4 
in the 1st lumbar to 91*4 in the 5th, and the mean general index of the entire series was 
106. Dr. Cunningham has stated in his abstract the mean lumbar indices in seventeen 
Australian spines, and obtained from them a mean index 107'8, which was somewhat 
higher than in my measurements. The range in his series was from 119'8, the mean 
index of the 1st lumbar, to 90*4, the mean index of the 5th. In his series six males had 
a mean lumbar index of 110*1, and four females of 103*1. 
In my single male Bush skeleton the collective vertical diameter of the bodies of the 
five lumbar vertebrae was 108 mm. anteriorly, and 115 mm. posteriorly. In the 1st, 
2nd, and 3rd lumbars the posterior diameter exceeded the anterior ; in the 4th these 
two diameters were equal, and in the 5th the anterior diameter was 1 mm. greater than 
the posterior. The proportions in this skeleton closely corresponded to what was seen in 
the Australians. The general lumbar index was 106, and the index of the 5th lumbar 
vertebra was 95. Dr. Cunningham has given 106*6 as the mean lumbar index of three 
Bushmen, whilst the mean index of the individual vertebrae ranged from 115*9 in the 1st 
lumbar to 95*3 in the 5th. 
In my series of Andaman Islanders' skeletons only two had the lumbar vertebrae com- 
plete. In one the vertical diameter of the five vertebrae collectively was 113 mm. anteriorly, 
and 112 mm. posteriorly; in the other 125 mm. anteriorly, 124 mm. posteriorly. The 
1st and 2nd lumbars in both skeletons were thicker behind than in front. The 3rd 
lumbar in one skeleton was of equal diameter on both aspects, and in the other was 
1 mm. thicker behind than in front. In both skeletons both the 4th and 5th lumbars 
were thicker in front than behind, in the one skeleton the anterior surface of the 5th 
lumbar being 3 mm., in the other 5 mm., thicker than the posterior. The mean index 
in the two skeletons diminished from 111*3 for the 1st lumbar to 84*2 for the 5th 
(Table X.) ; the mean general lumbar index of the two skeletons was 99. Dr. Cunningham 
