276 Proceedings of Royal Society of Edinburgh. [sess. 
normal. The inferior turbinate, a cartilage bone, is also small and 
well ossified. 
Temporal bone . — The membranous portions (squamo-zygomatic 
and tympanic) are normal, but the petro-mastoid, developed in 
cartilage, is distinctly smaller than normal, and its cranial surface is 
irregular in form, the prominence of the superior semicircular canal 
and the floccular fossa being indistinct. The auditory ossicles are 
well ossified, and are practically normal in size. 
All the foramina piercing the cartilaginous portion of the base of 
the skull are distinctly diminished in size. The bones forming the 
vault of the skull — frontals, parietals, and upper part of supra- 
occipital are normally ossified, but the calvaria presents certain 
peculiarities. Thus all the fontanelles, mesial and lateral, are en- 
larged, and the two halves of the frontal and the two parietals are 
further apart than normal. The reason of the enlargement of the 
fontanelles is found in the fact that the base of the skull is so short 
that an abnormal separation of the bones of the vault was necessary 
to give space for the growing brain. For the same reason the 
vertical plates of the frontal are bulged forwards. There is, 
therefore, a general enlargement of the vault of the skull compen- 
satory in character. All the facial bones developed in membrane 
are practically normal. 
The lower jaw is the only one presenting any peculiarity. The 
ossification of this bone is complex, it being formed partly in 
cartilage and partly in membrane. On the whole it is distinctly 
smaller than normal; thus it measured 3 ’3 cm. along the lower 
body of the body from the angle to the symphysis, as compared 
with 4*5 in a normal specimen. The vertical depth of the body 
was very slightly diminished. 
The portion of the body in front of the mental foramen was of normal 
length, but its anterior extremity corresponding to the central incisor 
was partly cartilaginous and imperfectly united with the rest of the 
bone. This is the only portion of the lower jaw which is formed 
by the ossification of Meckel’s cartilage, the greater part of the body 
of the jaw being ossified in membrane external to Meckel’s cartilage. 
The small size of the lower jaw was evidently due to the fact that 
its posterior portion is ossified in cartilage. 
Before proceeding to the examination of the other parts of the 
