The skeleton in the flying lemurs, Galeopteridae / by R.W. Shufeldt.

  • Robert Wilson Shufeldt
Date:
1911
Catalogue details

Licence: In copyright

Credit: The skeleton in the flying lemurs, Galeopteridae / by R.W. Shufeldt. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

    38/72 (page 186)
    of plates), while in others it is very complete and rather thick (3, 3). Again, the scapula in different individuals is prone to vary in some of its characters, but to no greater extent than we ffnd among a series of human scapidas chosen from adults of the same sex and race. One of the skeletons sent by McGregor (2) has the scapula thoroughly ossified, quite perfect, and presenting all the characters of the bone as they occur in our subject. It is here seen to be a distinctly triangular bone with all its parts highly developed. Facing upward and inward, the glenoid cavity is rather extensive; the concavity is j)ear-shapcd in outline, and the small end extends upon the base of the coracoid process. From the glenoid cavit}^ to the inferior angle we have the extenial or axillary border, which here presents a notable departure from mammalian scaj)ula' generally in being broad and flat for ahnost its entire length to the lower point of the bone. This flat border is of uniform width to its termination, that is about 4 milli- meters, and appears as if it had been formed by bending that much of the blade of the bone abruptly, at a right angle toward the .s])ine, thus creating a deep “infraspinous fossa,” Init adding nothing to the ventral aspect of the bone, 'the vertebral or internal border is not as long as the axillaiy one, and its margin is only very slightly thickened for its entire length. The two bordei-s make an angle of 30° with each other, and the angle thus formed, or the inferior angle of the scapula, is here rounded off’ rather than acute; the sizable bit of the apex, evidently formed from the usual independent center of ossification, has not yet united with the blade of the bone.^” The superior border, extending from the inner base of the coracoid process to the angle which in anthropotomy is known as the “superior angle,” is here sharp and uniformly concave throughout its length. The superior angle is about a right angle and is rounded as in most mammalian scapula'. The superior border is only about one-half as long as the axillary one; the vertebral border stands between the two in this respect. A supra- scapular notch hardly exists in the superior border near the coracoid process; indeed, although the greatest concavity of the border here is where it usually occurs, no such break in its continuity is to be dis- tingui.«hed. At its narrowest part the neck of the scaj)ula measures just 1 centimeter, and likewise this is the thickest part of the bone antero-posteriorly, it being about 0..5 centimeter just within the glenoid cavity. This indicates that the animal was still in a subadult stage when killed. Complete union has taken place in the other two specimens (1 and 3) from which we conclude that they are more advanced in age. Tn the human species it is not until the sixteenth year that this epiphysis unites with the rest of the scapula at this point.