MAN article
MAN: A morphological comparison of two crystal skulls
MAN
A monthly record of Anthropological science
Vol. XXXVI
July 1936
Nos. 142-178
Contents
Plate I-J. Crystal skulls
ORIGINAL ARTICLES:
142. A morphological comparison of two crystal skulls. G.M. Morant. With Plate I-J and Illustrations.
143. Comments on the morphological comparison of two crystal skulls. Adrian Digby
144. Two crystal skulls: Dr. Morant’s reply to Mr. Digby’s comments
145. Two crystal skulls: Further comments by H.J. Braunholtz
A morphological comparison of two crystal skulls
By G. M. Morant
142 It appears that there are only two life-size representations of the human skull in rock-crystal known to be in existence. One of these is preserved in the Department of Ethnography of the British Museum and the other is in the possession of Mr. Sydney Burney. The following note concerns a comparison of the two specimens considered solely from a morphological point of view. The writer is indebted to Captain T. A. Joyce and to Mr. Burney for permission to handle and measure the precious objects and for the photographs here reproduced.
The right-profile and full-face photographs (Plate I-J and Fig. 1) convey an excellent impression of their general appearance. Identical or closely similar features which may be noted are almost perfect bilateral symmetry, the absence of any indication of sutures, the almost complete absence of a glabellar prominence or superciliary ridges (this and other characters suggesting femaleness in both cases), the slight curvature of the median sagittal sections of the vault and occiput, and the absence of any indication of the position of the lambda. The median section of the frontal region of the Burney specimen is rather more protruding than that of the other, but there is not the slightest suggestion in either case that the skull (or skulls) copied was artificially deformed. Seen from the front the brain-boxes appear well-filled, but not unnaturally so. Other unusual features common to the two specimens are the unnatural straightness of the median sections of the facial skeletons, the prominence of the anterior nasal spines, and the verticality of the rami of the mandibles seen from in front. The minimum breadths of the rami in both cases are found as low down as possible, so that one terminal of the measurement is at the angle (gonion). This last feature is quite exceptional, but mandibles exhibiting it are occasionally found in long series.
The only marked differences between the crystals are observed in the conformation of the facial and basal regions. The British Museum skull is in one piece, but the Burney has the lower jaw detached. The former has unnaturally round orbits and little attempt was made to excavate the zygomatic arches or mastoid processes; the latter indicates all these features in a far more natural way. The dentitions are indicated as complete in both cases, and practically no attempt was made to show the shapes of different teeth, though in this respect, also, the Burney skull is more life-like than the other. In a word, the facial part of the British Museum specimen is a crude representation, and that of the Burney crystal was far more successful judged from an anatomical point of view. A circular depression on the base of the former indicates the position of the foramen magnum, but apart from this no attempt was made in either case to show any details in the basal region.
Owing to the absence of sutures, few of the usual measurements can be taken at all accurately. The most reliable ones are for the glabellar-occipital length 177, 174 (the reading for the British Museum specimen being given first); maximum calvarial breadth 135,140; cephalic index 76-3, 80-5 ; bizygomatic breadth 117, 117; nasal breadth 22, 24; breadth of left orbit 34-5, 37-5; height of left orbit 37, 33-5; left orbital index 107-2, 89-3. No one of these measurements would be at all exceptional for an actual skull except the orbital index for the British Museum specimen which appears to be slightly removed from the human range for this character. At the same time the other measurements are in remarkably close accordance. A more interesting comparison can be made by superposing the outlines. The lateral photograph of the British Museum crystal (Plate I-J A) shows the right profile exactly. That of the Burney specimen (B) on the same plate is not a perfectly true profile view as both mastoid processes and both sides of the nasal aperture can be seen, but the divergence from the norma lateralis is only slight. These photographs were copied and enlarged prints of each made exactly natural size. Tracings of the outlines and a few other lines which could be easily seen were then made and superposed, the result being given in Fig. 2A. The method of superposing the tracings to give the best agreement was clearly to place one Outline of the facial skeleton on top of the other as these two are almost identical. The outlines of the brain-boxes then diverge to an appreciable extent, but certainly not more than would those of two female skulls picked at random from a series representing a single race. The margins of the orbits are not far apart and marked divergence is only found between the two pairs of lilies representing the zygomatic arches. A diagram showing the superposed natural size tracings derived from the full-face photographs Fig. 1 A-B is not given as it would be misleading to some extent. Both show full-face views almost exactly, but to correspond with the superposition made in Fig 2A the British Museum specimen should show less of the cranial vault than the other does, and it actually shows more. The photographs available are sufficiently close to the ideal ones, however, to make it possible to say that the following relations would be found from enlargements obtained from the latter; the outlines of the lower jaws, the teeth lines and the nasal apertures would be practically coincident; the breadth at the zygomatic arches would be identical, but the difference in the forms of the arches would again be apparent; immediately above them the outline of the Burney skull would fall outside the other (to the extent of about 2 mm. on either side), but they would then approach again until close to the vaults where the slight difference in height would again become apparent; finally, the orbits would be seen to be higher in the Burney specimen. The close correspondence between the two outlines is again remarkable.
The above comparison makes it impossible to avoid the conclusion that the crystal skulls are not of independent origin. It is almost inconceivable that two artificers, having no connection with one another, and using different human skulls as models, should have produced specimens so closely similar in form as these two are. In the writers opinion it is safe to conclude that they are representations of the same human skull, though one may have been copied from the other. The only essential differences between them are clearly due to the fact that in fashioning the Burney crystal care was taken to make some features, which are crudely modelled in the other, more life-like, as in making the lower jaw separate and giving the orbits, zygomatic arches and mastoid processes the similitude of their natural forms. Ethnologists would probably suggest that if one was copied from the other then the more finished is the later, but it is not easy to accept this explanation. We may suppose that the British Museum specimen was modelled from a human skull, and that at some later date the original crystal was copied by another craftsman who used another human skull to guide him in making some features more realistic. But this craftsman must be credited with some knowledge of anatomy, for otherwise the substitution of a false model for the real one would have been very likely to lead to some anatomical abnormalities in his product, although none are actually observed. No decisive answer can be given to questions of this kind, but, whatever the relation between the two artefacts may be, it is practically certain that they are primarily derived, directly or indirectly, from a single human prototype. The question of what race this belonged to is also one which cannot be answered decisively. Comparisons between Fig. 2A and type contours available for English cranial series suggests that it was as orthognathous, or more orthognathous, than the average European cranium. An American Indian skull would be expected to have more projecting jaws, and a broader and higher facial skeleton. Intra-racial variation is so great, however, that it would be rash to assert that an American Indian could not have possessed the skull which was copied.
Comments on the morphological comparison of two crystal skulls
By Adrian Digby, British Museum
143 Dr. Morant’s morphological comparison of 11U the two skulls is of considerable interest, and while any suggestions which may be made are of necessity speculative, it is interesting to consider the implications of Dr. Morant’s opinion that both models are related in so far as they are ultimately based on the same original. Three possibilities are open to us. First, that both models were made at some time directly from the original postulated by Dr. Morant. Secondly, that the Burney skull was made directly from the original and that at a later date the British Museum specimen was copied from it by a man knowing considerably less anatomy than the maker of the Burney skull. The third explanation, which is favoured by Dr. Morant, is that the Museum skull was copied from an original skull and that at a later date the Burney skull was a sort of composite copy relying for its proportions on the skull now in the Museum and for its anatomical detail on some human skull in the possession of the carver.
Each of these hypotheses is open to grave difficulties. If it is assumed that both models are modelled directly from the same original why is there so much difference between the two? The stylized Museum specimen with the lower jaw carved integrally would hardly be the work of the same man who produced Mr. Burney’s accurate model. Also it is probable from the stylistic differences that they are not contemporary. This means that the original 4 source ‘ skull was a particularly important skull, probably belonging to a culture hero or warrior, a ‘ Museum piece,’ as it were, to which various craftsmen would have access, or alternatively that the skull was the property of a particular family of craftsmen, and that one model was made by a descendant of the maker of the other. Dr. Morant draws particular attention to the feminine or infantile characteristics of both skulls; so it is unlikely that the model is based on a ‘ Museum piece,’ for such a skull would almost certainty be a representation of the deathgod, a male character, or of a warrior. But the writer can conceive no other set of circumstances which would, without the use of pure coincidence, account for different craftsmen at different times having access to the same original.
The technique will not help us to settle their relative ages for in neither case is there any trace of identifiable tool marks, and it is certain that neither specimen was made with steel tools. On the teeth there is no trace of a lapidary’s wheel which would betray one or both specimens as being of comparatively modern origin. But the other crystal skulls, notably the specimen in the Trocadero Museum (G. F. Kuntz, ‘Gems and ‘Precious Stones of North America’), and a miniature specimen in the British Museum, not only have the lower jaw carved integrally with the rest, but the partly conventional circular drillings for the eyes are found more nearly akin to the British Museum specimen than to Mr. Burney’s.
The second suggestion, that the British Museum skull is derived from (one might almost say descended from) the Burney skull is not impossible. Prof. Balfour has frequently demonstrated the process of evolution or degeneration which can occur when a design is copied by different people. On these grounds it would be quite possible to argue that since the British Museum crystal skull resembles its ‘ ancestor ‘ less than Mr. Burney’s resembles the same ‘ ancestor,’ it must be a more distant relation as it were.
But we must remember that the Museum skull is more like the other known specimens, especially about the jaw and zygomatic arches, and therefore more likely to date from Mexican times than Mr. Burney’s. This last fact favours the view that Mr. Burney’s skull is, as it were, the offspring of the Museum skull, and a real skull in which the profile of the Museum skull has been preserved, but improved on by a later artist’s observations of a real skull. This of course is possible, but it is extraordinary that anybody wishing to carve a skull out of rock crystal, and taking a real skull as his model should modify its dimensions to fit those of another crystal skull which he would see was but a poor copy of nature. It shows a perverted ingenuity such as one would expect to find in a forger, but Mr. Burney’s skull bears no traces of recent (metal age) workmanship; so this suggestion may almost certainly be dismissed.
There are large objections to each of the three explanations of the similarity between the two skulls, and it is very hard to agree that with Dr. Morant’s view both skulls are related. It is only with great trepidation that I venture to disagree with such a distinguished anthropologist as Dr. Morant, but technological considerations make it very hard to agree with him.
Dr. Morant’s comparison is very impressive, especially his superimposed plan (Fig. 2A), but-one of the difficulties which must have faced Dr. Morant has been the difficulty of orientating the two crystal skulls in exactly the same plane. There do not seem to be any key points which will aid in orientating the two skulls on the Frankfort plane or Thompson’s plane. The only alternative was to superimpose the two profiles and orientate them until they seemed most nearly coincided. Dr. Morant has done this, paying particular attention to the facial regions. This makes the frontal portion of Mr. Burney’s skull higher than that of the Museum specimen, and the basal regions lower. If, instead, two profiles are superimposed (Fig. 2B.) So that the two outlines of the brain-box portion of the skull coincide as nearly as possible it will be found that the lower portions of the zygomatic arches are more nearly parallel (though that of the Burney skull appears slightly below that of the Museum skull instead of slightly above it), and the face becomes slightly more orthognathous, and therefore slightly more European in type than the Museum specimen. This is all in accordance with the deductions which are to be drawn from general appearance of the two skulls. It would, however, be extremely rash to suggest that either skull was of European rather than Mexican manufacture.
Until further evidence is available on the whole subject of crystal skulls no definite conclusions can be reached, and in spite of the remarkable similarity of outline which Dr. Morant has demonstrated, it still appears unwise to assume that the two skulls are based on the same original.
Two crystal skulls. Dr. Morant’s Reply to Mr. Digby’s Comments.
144 Mr. Digby allows me to comment on his remarks relating to the way in which the outlines of the two specimens are superposed in Fig. 2A. It seems to me that there is full justification in such a case for arguing from the relations found when the best possible fit has been obtained, without regard to any arbitrary plane of the skull. This appears to be the one shown when account is taken of both facial and calvarial outlines. If the calvarial are considered alone a rotation of one might be considered to give a rather better agreement, though the regions of the nasal bridges and the facial outlines will then diverge markedly. The remarkable resemblance between the median outlines of the facial skeletons seems to be quite sufficient in itself to indicate that there is a direct relation between the two ’skulls.’ If one was copied from the other, than it may well be that this part was copied first and that the shape of the remainder of the block of crystal did not permit as exact a reproduction of the form of the brain-box.
Two crystal skulls. Further Comments by H.J. Braunholtz, British Museum
145 The B.M. skull is definitely far more ‘coventionalized’ than the Burney specimen. The cranium has a perfectly smooth contour, the eyes are circular, and the teeth merely indicated. These peculiarities are in accordance with the general character of ancient Mexican art; It would be hard to quote a single specimen in which anatomical detail is fully and faithfully recorded without some degree of ‘stylization.’ This is particularly the case with the Aztec stone masks and figures of deities, most of which are highly conventional.
On the other hand, the Burney skull pays considerable attention to the correct rendering of detail; minor protuberances on the- cranium are carefully modelled; as Dr. Morant points out, the orbits approximate to nature. Such realism seems beyond the ordinary range of Aztec art, and gives the skull the character almost of an anatomical study in a scientific age.
In any comparison of these two skulls, this difference of spirit seems to me to be a crucial factor, and one which should be given full weight in drawing conclusions.
Tags: Adrian Digby | crystal skull | G.M. Morant | Mitchell-Hedges skull | Sydney Burney
