We have made this attempt to describe and interpret the endocranial cast of
Sinanthropus
in deference to the wishes of Professor Davidson Black.* When he submitted to the Royal Society his preliminary report (Black, 1933,
a
), he explained to us that he did not regard it as a disadvantage that his paper was incomplete, because it opened the way for those who had opportunities for comparing the cast with those of other human fossils and actual brains of primitive men and apes, to undertake the necessary work of comparison and interpretation, and we willingly undertake this duty. Each of us has independently studied the actual fossil skull in the Union Medical College at Peiping and examined the beautiful cast made by Professor Davidson Black from the actual fossils, and we should like to express our gratitude to him for these opportunities and many other kindnesses which he showed us. In studying the endocranial cast obtained from the Piltdown skull one of us (G.E.S.), years ago, was impressed by the extraordinary resemblance presented by the form of the brain in this extinct member of the human family to that of the primitive brain of a modern human being, a Sudanese negress (Elliot Smith, 1927, figs. 40 and 41). The other (J.L.S.) was impressed by the remarkable likeness to the endocranial cast of
Sinanthropus
of the brain of the Bushwoman, described in 1865 by Professor John Marshall. The recognition of these facts adds particular importance to the consideration that both the authors of this communication have served an apprenticeship to the task by examining large series of primitive brains, aboriginal Australians (J.L.S.) and Sudanese negroes (G.E.S.), and have devoted some attention to the comparison of the brains of the anthropoid apes and primitive men. In attempting to interpret the significance of the endocranial cast of
Sinanthropus
special attention must obviously be paid to comparison with the casts of
Pithecanthropus
and
Eoanthropus
. The comparison with the brains of the larger apes is also important, throwing light as it does upon the characters one ought to expect to find in extremely primitive human brains. In attempting to convey some real conception of the nature of the form of the brain we have resorted to the use of series of contours, figs. 10-14, so that the reader at a glance can obtain a graphic expression of the distinctive peculiarities of form. * The misfortune of his premature death deprives us of the pleasure of presenting this memoir to him.
On the presence of hæm-agglutinin and hæmolysins in the blood obtained from infectious and non-infectious diseases in man. (Third report.)