FrazER—On a Great Sepulchral Mound. 45 
ence, and it therefore constitutes an important anatomical variety of 
idiotcy. The well-known Hottentot Venus, of whom I possess a por- 
trait drawn to scale, who was exhibited as a show in different parts of 
Europe several years ago, and whose skeleton is preserved in a Parisian 
museum, was an example of this idiotic demi-microcephale. Similar 
skulls are occasionally to be noticed in all our large asylums for the 
imsane and for idiots; and the Aztec children, so-called, who were 
shown in Dublin lately, are specimens of microcephalic idiots with 
dwarfed bodies. 
Two portions of a skull of unusual thickness were obtained. In 
some parts it is almost one-third of an inch thick, measuring 15 milli- 
metres exactly. This appears to be a natural and healthy bone, the 
thickening being caused by no disease whatever. 
In considering the shapes of the skulls obtained that belonged to 
adults, for classing them, I have selected out of a large number three 
specimens which will illustrate the three great divisions of crania 
which are usually described. Of these No. 44 will represent a doli- 
chocephalic skull, No. 21 an intermediate mesaticephalic form, and 
No. 22 is brachycephalic. 
These classifications, which depend on the relation or ratio that 
the antero-posterior diameter will bear to the transverse measure- 
ment of the skull at its widest part, is calculated by the formula 
Trans. diam x 100. 
: > but such calculations are facilitated by the ex- 
an. post. diam. 
cellent Tables of Professor Flower, published in the last Catalogue of 
the Museum of the Royal College of Surgeons of England. The index 
varies from 
750 and under for dolichocephal, 
750 to 800 for mesaticephali, 
800 and upwards for brachycephali. 
Now the cranium No. 44 affords us an index so low as 704. This 
is an exceptionally low result, for the skull of the average Australian 
savage reaches 71:49, and even the Hottentot amounts to 72°42. This 
cranium will agree in measurement and shape with those long and 
narrow skulls that are found in Long Barrows. It has lost the face 
and lower jaw. 
No. 21, the mesaticephalic skull, is found to possess when measured 
an index of 754; this corresponds with the skulls of the Dolmen 
builders, and that of the Ancient Egyptians. It also corresponds 
exactly with the index ascribed by Messrs. Thurnam and Davis to the 
ancient Irish skull. From several considerations I am led to believe 
this is a typical Celtic or Irish cranium. 
But on examining the skull which I first obtained, No. 22, and 
which, I believe, was that interred with the sword and spear, having 
the deep sword-cut in its frontal bone, the index rises to 833; this is, 
