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This paper discusses how the evolving hominid architecture of the arteriovenous system through the cranial base diverted foreseeable pathology in the human brain. Bipedal upright posture was an early adaptation in mosaic morphological pattern changes in hominid evolution; a key feature, the ability of blood to flow either to vertebral or internal jugular venous systems. Encephalization punctuated hominid evolution, its vulnerable feature, a lower threshold for thermal damage. Comparative analysis of ape and human skulls show “fingerprint” structures, revealing big changes in pattern complexity of the cranial vascular tree. Clues to structural/functional changes span data for apes, humans, and hominid fossils. Here, the increasing vascular network, Australopithecus to Homo sapiens, necessitated changes in the blood flow patterns. The transverse-sigmoid (T/S) and occipital-marginal (O/M) venous networks accommodated hydrostatic changes of blood flow, regulating temperature uniquely: the O/M system enlarged, allowing blood to flow straight down into the vertebral plexus without cooling, and added a vast network of emissary/diploic veins, acting as a brain cooling “radiator.” This O/M system was fixed in the Australopithecus robustus lineage, p = 0.000001; high frequencies of emissary foramen were selected for over time. Ontologically, the human neonatal O/M system is fully developed; emissary/diploic veins are established by age 5, setting conditions for selective brain cooling. The Radiator Theory is the evolution of the functionally efficient brain cooling system, fixed in the A. robustus lineage, tying hydrostatic consequences of bipedalism with release of a “thermal constraint” on the encephalizing brain, and reflected in our own ontogeny.

A GLIMPSE INTO MODERN PALEOANTHROPOLOGY: In the last decades, paleoanthropology has been deeply modified, changing from a descriptive and historical science to a more quantitative and analytical discipline. The covariation of multiple traits is investigated to study the evolutionary changes of the underlying anatomical models, mostly through the introduction of digital biomedical imaging procedures and of computed geometrical analyses supported by multivariate statistics. FUNCTIONAL CRANIOLOGY: The evolution of the human cranium is consequently considered in terms of functional and structural relationships between its components, largely influenced by the allometric variations associated with the increase in the relative cranial capacity. In the human genus, the changes in the face, base, and neurocranium are characterised by a mosaic variation, in which adaptations, secondary consequences, and stochastic factors concur to generate a set of anatomical possibilities and constraints. SYSTEMIC PERSPECTIVES TO THE EVOLUTION OF THE HUMAN CRANIAL MORPHOLOGY: Concepts like morphological modularity, anatomical integration, and heterochrony represent key issues in the development of the current human evolutionary studies.

M an is not the largest of the pri­ mates (the gorilla is larger), but he has the largest brain. How did this come about? The question is hardly a new one, but a considerable amount of new evidence is now available to those in search of the answer. In brief the evidence suggests that, contrary to what is widely believed, the human brain was not among the last human organs to evolve but among the first. Neurologically speaking, brains whose organization was essentially human were already in existence some three million years ago.

Twenty new hominid specimens were recovered from the East Rudolf area in 1973. New evidence suggests the presence of at least three hominid lineages in the Plio-Pleistocene of East Africa.

The late Pleistocene human remains from Kow Swamp display archaic cranial features which suggest the survival of Homo erectus in Australia until as recently as 10,000 years ago.

Studies on a living and freshly dead male ofM. assamensis at Y.R.P.R.C. supplemented by notes on a living pair and their male offspring observed at the Z.S.L., enable us to supplement existing data on the somatology, craniology, dental anatomy and behavioural features of the species. Collectively the new data necessitate taxonomic revision of the status of the species, viz: its removal from immediate association withM. mulatta (subgenusMaimon) and alignment within the subgenusZati. Zoogeographical discontinuity in this subgenus is compared with that of the subgenusSilenus.

Four specimens collected last year from East Rudolf are provisionally attributed to the genus Homo. One, a cranium KNM-ER 1470, is probably 2.9 million years old.

The general morphological and the fissural character ofDubois' andKoenigswaldsPithecanthropi andBlack'sSinanthropus (E) strongly suggest that thePithecanthropus brain had more anthropoid features than theSinanthropus brain.

A skull with numerous Homo features was discovered at Sterkfontein, near Krugersdorp, Transvaal, in August 1976. It stems from member 5 of the Sterkfontein Formation, with stone tools and with fauna pointing to an age of 2.0-1.5 Myr. The underlying member 4 contains Australopithecus africanus, no stone tools, and fauna dated 3.0-2.5 Myr. The new find supports the view that the Sterkfontein toolmaker was not the earlier A. africanus, but a later hominid related to Homo habilis. By a remarkable double coincidence, the first pieces of the new skull, Stw 53, were found on August 9, 1976, 40 years to the day after Robert Broom's first visit to Sterkfontein, while the last part came to light on August 17, the 40th anniversary of Broom's first discovery of a hominid cranium at Sterkfontein. Although most of the fragments were found in a decalcified pocket of cave earth, one large part of the calvaria was still present in the calcified wall of the pocket, thus establishing indisputably the provenance of the specimen.

THE portion of a hominoid mandible (KNM*–FT 45) found in 1962 at Fort Ternan in Kenya has been referred provisionally by Leakey1 to Dryopithecus (sensu strictu). Simons2 has agreed essentially with this. Other primates found at Fort Ternan include the maxilla fragments of Ramapithecus wickeri (Leakey) 1962 (ref. 3), several individuals of Pliopithecus, and several isolated teeth attributed to Proconsul and Oreopithecus. By size alone the mandibular specimen (KNM–FT 45) can be distinguished from all these except R. wickeri. A detailed examination of occlusal relationships between the upper teeth in the maxilla of R. wickeri (KNM–FT 46)† and the two premolars in KNM–FT 45 suggests that the two specimens belong to the same individual; and even if this is not so they definitely belong to the same species. Simons4 and Pilbeam5 have argued that Leakey's taxon Kenyapithecus wickeri is a junior synonym of Ramapithecus punjabicus (Pilgrim) 1910 (ref. 6), but the evidence indicates at least a species difference, and this is the position I take here.

THE skull of Plesianthropus which we discovered on April 18 is in almost perfect condition ; but being the skull of apparently a middle-aged female, some of the sutures are closed and their positions difficult to determine. Still, many can be made out. We hope within a few months to be able to send for publication a complete account of the skull ; and when this is published the Plesianthropus skull will be almost as satisfactorily known as that of man or any of the living apes. As this complete account will probably be published to the world in less than a year, it will be unnecessary to give preliminary accounts of many of the interesting features ; but there are certain points which some English anatomists consider as of very great importance, and we will give here a short account of two characters which will be sufficient to prove that Plesianthropus is not just a chimpanzee, but a being of considerably more importance.

PROF. P. V. TOBIAS1 has produced a range of values for the cranial capacity of the ‘pre-Zinjanthropus’ juvenile from Bed I, at the F.L.K.N.N. I site at Olduvai Gorge, Tanganyika. This communication presents evidence which confirms Tobias's calculations.

In Olduway wurden in Bed I und unteren Schichten von Bed II neue Hominidenfunde geborgen, die alsHomo habilis benannt wurden. Sie zeigen, dass in Ostafrika zur gleichen unterpleistozanen Zeit zwei Hominidentypen lebten undZinjanthropus nicht langer als Trager der Olduwan-Kultur angesehen werden muss. Die Funde konnen zwei verschiedenen zeitlich aufeinander folgenden Formen zugeordnet werden, von denen der Typusunterkiefer aus Bed I enge Beziehungen zuMeganthropus palaeojavanicus zeigt, Maxillae und Mandibel von MNK II aus Bed II aber ausserordentlich starkPithecanthropus modjokertensis ahneln.

THROUGH the kindness of Professor Tobias, I recently spent five months in South Africa studying the endocranial remains of the australopithecines. I found substantial differences between my determinations of endocranial volumes and those previously published. Detailed descriptions of methods and morphological comparisons are in preparation.

IN a short paper which I published six years ago on the craniology of the yellow-skinned races of South Africa, I pointed out that the Hottentots and Korannas seemed to me to be very distinct from the Bushmen. The former have dolichocephalic skulls and are well-built men, often of tall stature: the latter are a small race with skulls that are nearly brachycephalic. The Hottentots of south-west Africa, and the Korannas of the Vaal River valley, while apparently branches of the same race, have certain distinguishing characters. The typical Hottentots are not improbably the primitive race contaminated by a considerable Bushman admixture; while the Korannas are apparently nearer to the primitive type, but with a considerable Australoid element.

PROF. HOLLOWAY has shown effectively that the partial endocast of Homo habilis provides a valid basis for estimating its cranial capacity, and even for a far greater range of angles along the sagittal suture than are anatomically likely. He has increased the maximum (biasterionic) breadth by as much as 10 mm and reduced it by as much as 20 mm and found a minimal effect on the cross-sectional area of the biparietal tunnel. It is of interest that the difference in biasterionic breadth between two reconstructions made in Nairobi and in Johannesburg was scarcely 2 mm. The first was made by Dr. L. S. B. Leakey and myself, with the auxiliary observational judgment of Dr. G. G. Simpson, Mrs. M. Leakey and Mrs. S. Coryndon; the second was made by A. R. Hughes and myself. The tolerance limits of our reconstructions were 2 mm; Prof. Holloway has validated the method for a range of 30 mm between the greatest and smallest biasterionic distances !

BETWEEN 1924, when the Taungs ape-man was discovered, and 1941, when the jaws of the baby Kromdraai ape-man were found, remains of many-individuals of this wonderful family, which some of us consider to be nearly related to man, were discovered; sufficient to show that in South Africa we may have the key which will solve the problem of the origin of man. But from 1941 until a few months ago, no further research was undertaken.

IN answer to Mr. A. T. Mundy's questions, it seems to me that it would be impossible in a young living ape, by artificial means, to prevent his frontal suture from closing, and if we could succeed in keeping it open I question if any marked increase in the size of the animal's frontal lobes would augment his intellectual capacity. It is not only the great size of man's cerebrum as compared with that possessed by anthropoid apes which gives him greater intellectual power, but, as I have stated in the passage quoted by Mr. Mundy from my Hunterian oration, the frontal and parietal lobes of the human brain are “far more perfectly developed than the corresponding lobes among anthropoid apes.” This is especially the case with respect to those motor and psychical areas of man's cerebral convolutions which control his power of intelligent speech; these areas of the brain are deficient in the anthropoid apes. It is probable that man's ability to make use of articulate language, and through this means to think, has led to the great development of the psychical elements of his brain. A comparison of the size and conformation of the cranium of Tertiary man with that of existing Englishmen is an indication of the length of time it has taken for the human cerebrum, and therefore intellect, to reach its present stage of evolution. Man and anthropoid apes we hold to be derived from a common ancestral stock; the former, under the action of natural selection and other causes, including, I think, not only an inherent capacity of cerebral but also of cranial growth, have gradually developed, whereas anthropoid apes, from arrest of cranial and cerebral growth, have not reached the standard attained by human beings; the difference between these two orders of beings, however, is one of degree, and not of kind.

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