72 
THE VOYAGE OF H.M.S. CHALLENGER. 
of 77 arc more difficult to arrange, but on the whole I am inclined to think that they 
approach more closely in shape to the dolichocephali than to the brachycephali. 
For the most part these skulls rested either on the mastoids or occipital condyles, but 
four touched the table behind with the lower part of the cerebellar fossae. In each 
specimen the frontal arc was longer than the occipital. In one the parietal and occipital 
arcs were equal, in the others the parietal exceeded the occipital. In four skulls the 
parietal exceeded the frontal. The Stephanie diameter exceeded the asterionic except in 
two specimens, in each of which the asterionic was 1 mm. the greater. In all, the 
interzygomatic diameter was less than the greatest breadth in the parieto-squamous 
region. The basi-nasal length was in three cases less than the basi-alveolar. No skull 
was metopic. 
As regards variations in individual skulls, Af. has an epipteric bone in the left pterion, 
and in the right pterion the squamous temporal articulated directly with the frontal. In 
three specimens one or at most two small Wormian bones were in the lambdoidal 
suture. H showed some want of symmetry in the occipito-parietal region, the left half 
of the occiput projecting behind the right ; the cranial sutures were unossified, except the 
lower third of the left coronal, which was obliterated. In several of the skulls a suture 
extended from the infraorbital foramen into the floor of the orbit and infraorbital canal. 
The vertical index of these mesaticephalic crania was 74 c.c. ; in two specimens this 
index was equal to the cephalic, and in one slightly above it, but in all the other skulls 
the cephalic index exceeded the vertical. The lowest basi-bregmatic diameter in the 
female series was 128 mm., the highest 137 mm. ; whilst in the male series the lowest corre- 
sponding diameter was 134 mm., and the highest 142 mm. The mean height of the female 
skulls was 132 mm., that of the males 138 mm. One of the skulls was prognathous, 
three orthognathous, three mesognathous, but the differences in the gnathic index 
did not correspond in any definite way with differences in the cephalic index, for the 
prognathous skull N, with a cephalic index 75, had a gnathic index 104, whilst 
the orthognathous skull T, with the same cephalic index, had a gnathic index of 
only 94. The nasal and orbital indices also showed a great range of variation, but 
there was no definite relation between these variations and that of the cephalic index. 
The mean internal capacity of the nine crania which it was possible to measure was 
1405 c.c, i.e., mesocephalic ; the mean of six males was 1427 c.c, that of three females 
1363 c.c. The mean of each sex was also mesocephalic 
