DR, J. CLELAND ON THE VARIATIONS OF THE HUMAN SKULL. 
139 
to 84f- ; in four Irish males, omitting from consideration the two which have undergone 
gravitation changes, it amounts to 84-| ; in three Greek, omitting both the skull which 
has gravitated and another (46) in which the orbito-frontal angle is anomalously large, it 
amounts to 83; in three German, omitting the two which have gravitated, it amounts 
to 82-g-; in two Australian, 82 ; in five Negro skulls, 81 ; in five Scotch males, omitting 
the Old Officer, it amounts to 78f; and in five French, omitting the Old Knight, it 
amounts to 76f. Thus there are Kafirs and Irish at one end of the series, French and 
Scotch at the other, and Germans and Negroes in the middle. 
Whatever of inaccuracy has been imported into the measurement of this angle by the 
choice of the optic foramen as the posterior limit of the frontal floor, instead of a point 
in the mesial plane, makes the conclusion with regard to the Kafir, Negro, and Austra- 
lian all the more trustworthy ; for in these races the tendency of the lesser wings of the 
sphenoid as they pass outwards is to rise more than in European skulls, and thus to raise 
the optic foramina more than usual above the level of their origin, which makes the 
estimate of the orbito-frontal angle less than if it had been measured on a mesial 
section. But, further, an examination of some of the skulls, tracings of the mesial 
sections of which have been preserved, will be of itself sufficient to show how little a 
large orbito-frontal angle is to be trusted as an index of a superior type of skull. The 
Negro skull 63, a skull of a very inferior type, and the Australian skull 73, which, 
though rather well developed for an Australian skull, is yet a thoroughly characteristic 
specimen of that race, have the orbito-frontal angle respectively 83° and 82°; while 
the German skull 29, an extremely well-developed skull, has an orbito-frontal angle 
of 80°, and the young Scotch female skull 43, which, notwithstanding its defects, is 
a much more finely proportioned skull than Negro 63, has the same angle measuring 
only 74°. 
Deep frontal angle (General Table, column 32). — The testimony obtained by mea- 
surement of the angle formed at the foramen opticum by lines from the fronto-nasal and 
fronto-parietal sutures, and which may be termed the deep frontal angle, corroborates 
the conclusion that a forehead retreating on the floor of the anterior cranial fossa is by 
no means a character of the least advanced races. Indeed a glance over the list of dia- 
grams will show that a certain proportion exists between the deep frontal and orbito- 
frontal angles, so that it may be considered the normal condition at different ages and 
in different races for these angles to be together nearly equal to two right angles. The 
most extreme instances of the sum of the two angles falling short of 180° is the Carib 
skull 88, in which it is only 167 , the deviation being dependent in great measure on the 
largeness of the frontal sinus. The most extreme instances of the sum of the two angles 
exceeding 180 J are the large British skull 92, in which it amounts to 188°, and the five- 
year-old skull 16, in which it reaches 186°; and in both these it is the great length 
of the frontal part of the arch as compared with the orbital length which causes the 
deviation. The average sum of the orbito-frontal and deep frontal angles in adult male 
skulls, omitting, as before, those which have undergone gravitation changes, comes to 
about 176° alike in the Kafir, Negro, Australian, Hindoo, Greek, Scotch, French, and 
