35° or 40° in man, presents great differences, as is shown by the appended wood-cuts. I give no measurements, as the difficulty of making accurate ones is quite out of proportion to their value. The difference is in part, but not wholly, due to the development of the surface at the lower part of the axillary margin for the teres major. This muscle arises from the dorsal surface of the bone, but there is almost always a slight projection at this point from the anterior border, and occasionally it is developed into a projection of considerable size. Broca states that this is more common in negroes. I have no opinion to offer on this point, but I believe that this process does not stand in direct ratio to the size of the muscle. It is well marked on a very delicate scapula (Fig. 5), and on the other hand there is a large surface to

FIG. I.

this muscle with hardly any projection on a remarkably sharp bone (Fig. 4). An analogous case is the third trochanter, the occurrence of which, in my opinion, is quite uninfluenced by muscular development. The surface for the teres major projects out very strongly in the lower Simiidæ, Cebas, and Chrisothrix, according to Mivart. Its occurrence in man is probably (as in the case of the third trochanter) the appearance of a peculiarity of lower forms. The lower angle, however, varies considerably apart from the influence of this process.

The vertebral border (Fig. 2).—The most common form of scapula presents a line slightly curved at the lower part, and then straight as far as the root of the spine, from which point it inclines slightly forward till it ends at the upper angle. The forward inclination of the upper part, though varying in degree, is, so far as I know, constant, but the rest of the line varies much. Sometimes it is almost straight, sometimes the whole border of the bone is convex, sometimes the border below the spine is con

By another oversight Broca repeatedly calls this muscle "le petit rond."

cave. The different types are seen in the annexed diagram, but, better still, in some of the figures of the entire bone.

The superior border (Fig. 3) is also of uncertain shape. The superior angle cannot be considered apart from the posterior border. The diagrams show its variations so well as to make a description unnecessary. One of these is remarkable as showing the point truncated. None of these, however, show it rounded off in a way that equals the Boschiman scapula figured by Mivart. The variations of this angle are important, because they show that the length of the scapula, as used according to Broca's plan, is liable to vary according to the development of this angle. The

FIG. 2.

FIG. 3.

bone with the truncated angle has of course a scapular index decidedly different from the one it would have if the posterior and superior borders had been prolonged till they met in a sharp point. The differences in depth of the supra-scapular notch, which ranges from the merest deviation of the course of the superior border to a deep notch and then to a foramen, are well known. I have one specimen in which there is a foramen below a deep notch that is almost bridged over. It is the only case of the kind I have ever seen. The only allusion to its occurrence that I know of is in Humphry's "Human Skeleton."

Variations in the concavity of the body of the bone should also be mentioned. If a scapula be laid on a table with the ven

tral surface downward, it will usually rest on three points,—the coracoid, and the superior and inferior angles. The vertebral border, as a rule, forms an arch, the highest point of which is sometimes about 2 cm. from the table. In other cases this border barely leaves the table, and sometimes one or both of the angles mentioned are bent dorsally, so as no longer to be points of support.

On the dorsum the course of the spine and acromion deserve attention. By comparing the scapular and infra-spinous indices we get some idea of its obliquity. A high infra-spinous index with a moderate scapular index shows, of course, a greater obliquity, which is an ape-like peculiarity. When both are very high it shows simply a short, broad scapula. I called attention to the fact that one of the Kentucky mound-builders had a higher scapular index but a lower infra-spinous one than Broca's negro, Tom Blaise, which means that the former had the relatively broader scapula, but the latter the more oblique spine. A study of the one hundred and thirteen Caucasian shoulder-blades shows that the two indices present no great discrepancies. The average scapular index being 63.50 and the infra-spinous 85.83, I find but three with a scapular index of between 64 and 65 which have an infraspinous index below 85, and of these the lowest was 82.5. I find none at all with a scapular index above 65 and an infra-spinous below 85. Conversely, only seven having an infra-spinous index above 86 have a scapular index below 63. The lowest of these is 61.

Professor Mivart states that when the bone is so held that the long axis of the glenoid cavity is vertical, and that cavity is opposite the eye of the observer, the acromion is almost always higher than the coracoid in man, troglodytes, and hylobates. I do not remember any exception to this rule in man, but I find a good deal of variation in the direction of the line formed by the projecting edge of the acromion when the bone is thus held. It is not easy to determine what angle it forms with the horizon, and I shall give the mean very vaguely, as probably in the neighborhood of 45°, but I have seen it reach at least 65° on one hand and fall to 30° or less on the other. These two extremes are shown in Figs. 12 and 13. I have been unable to find that either of these degrees of inclination is associated with any particular shape of the bone.

1

The study of the range of variation in these separate parts leads one to the conclusion that very remarkable scapulæ could be constructed by a judicious selection and union of the most striking individual parts; but it would, I think, be difficult to make more remarkable ones than actually occur. I shall now call attention to some of the most curious specimens. Figs. 4 and 5 show respectively the lowest and the highest indices. The breadth is the same in each, but the length of the latter is little more than two-thirds of that of the former. The process for the teres major, though small, is clearly shown on the scapula of the mound-builder, but the other bone has a larger surface for the origin of the muscle, though there is but a slight projection at the anterior edge, which is confirmatory of the views expressed above. Figs. 6 and 7 have already been alluded to as widely different forms, having almost identical indices. Each is a peculiar bone, but the sharp one is the more uncommon. Figs. 8 and 9 are also in strong contrast to each other. The posterior borders have been figured, but the striking effect is shown in the figures of the whole bones. Each is very peculiar and in a different way, though neither has a remarkable index. Fig. 10 represents a wonderfully long bone,' being 20 cm. It is a remarkable specimen, and is among those having the lowest indices. The scapular index is 56.5, and the infra-spinous 76.3. The original of Fig. 11 (scapula index 58.8 and infra-spinous 72.3) is figured because it belonged to a negro and yet had indices far below the mean of Caucasian bones. A comparison of these bones shows assuredly remarkable diversities of form. It is easy to find bones of different species of animals that differ less from one another than do these human ones. I am unable to say what remarkable forms might be seen in a large collection of the shoulder-blades of the Felidæ, but I know that a small collection shows no such range. Even the scapula of the bear differs no more from that of the tiger than some of these from one another. A few notes on the anthropoid apes will be found in the appendix.

What influence the height, the muscular development, the health, and the occupation of the individual may have on the shape of the scapula, and indeed on the skeleton in general, The mate to this bone is the longest I have measured, exceeding it by more than I mm., but it has, unfortunately, been injured.

cannot as yet be much more than guessed at. The question suggests a field for inquiry, which has as yet hardly been opened, but which in the course of years may bear a rich crop. Something has been done in this direction by Mr. W. Arbuthnot Lane, of London.1

Livon found that in women both indices were higher than in men, while, as above stated, Broca found the reverse, but in very small series. I do not feel convinced that Livon's are large enough to put the fact beyond question, and certainly it would be rash to draw any conclusion as regards a single individual. Probably the actual size of the bone, and more particularly that of the glenoid cavity, are the best indications of the sex that the bone offers, and these are of but little value.

It must be remembered that the great range of individual variation does not necessarily destroy the value of Broca's indices, but it shows that the method must be applied to large series of bones from well-marked races. It is gratifying to find this view supported by no less an authority than Sir William Turner, who writes, “For I gather from my own measurements and those of other observers, that the range of variation in the relative length and breadth of the scapula is very considerable in the same race, so that it needs a large number of bones to enable one to obtain an accurate idea of the mean of any race." 2

APPENDIX.

THE INDICES OF ANTHROPOID APES.

Both Broca and Flower and Garson published the indices of anthropoid apes in their papers, which have been referred to so often. As the number of observations is necessarily small, I am glad to be able to offer a few additional ones. Broca gives the indices of ten gorilla skeletons, of five chimpanzees, of one orang, and of seven gibbons. Flower and Garson give the indices of sixteen bones of the gorilla, of twenty-one of the chimpanzee, of seventeen of the orang, and of eight of the gibbon.

The Pathology of Changes produced by Pressure in the Bony Skeleton of the Trunk, Guy's Hospital Reports, vol. xliii., 1886.

2 It is proper to mention that this paper had been written and sent to the NATURALIST before I had seen Professor Turner's remarks on the scapula in the "Challenger" Reports. Through the courtesy of the editors I have had an opportunity to modify my paper here and there by quoting from his work.