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.

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    unciform, magnum, trapezoid, trapezium, and scaphoid. Scaphoid is a small compressed bone, but is larger than pisiform; it has hut a single articular facet covering its entire mesial aspect that articulates with a similar facet on semilunar. It is connected with the trapezium by liga- ment only.-^ Trapezium of the distal row is only exceeded in size by the unciform. It is of an irregular cuboidal shape, with articular facets tor the proximal end of pollex metacarpal, trapezoid, and lunar. Above it, attached by ligament only, we find the scaphoid, while mesially it presents a small facet to the proximal end of index metacar])us. Having very nearly the same form and size, either being parallelepipedal with respect to the former, the tiapezoid and os magnum articulate with each other and both with semilunar. Trapezoid also articulates with the metacarpus of index digit, as os magnum does with the same bone of the middle finger. Unciform is a cube of irregular shape, the last car])al in the distal row on the ulnar side, that articulates with lunar, cuneifonn, and the metacarpus of minimus digit, and the inner side of the base of the meta- carpus of the fourth })halanx. Its palmar process is but feebly developed. The maims of Cjjnocephalus is large in proportion to the size of the animal, and exliibits in its skeletal morphology the chief uses to which it is put, that is, being fitted to serve the purpo.ses of climbing rather than of prehension. It is especially long and rather narrow, being armed distally with very efficient and powerfully hooked claws. It is a pentadactyl member with a short pollex and four elongated digits. All the phalanges composing these digits present the usual characters seen among ordinary small mammals. Theii' shafts are very nearly straight and quite cylindrical, while their distal extremities, or heads, sup])ort the usual double troehlete for articulation with the phalanx iiext beyond them in each instance. The base of each of these long bones is larger than its head and also presents an articular facet, which is oval and concave to receive the head of the phalanx next behind it. d'he ungual, or distal, joints are entirely different and will be described further on. The metacarpus consists of five bones; distally they articulate with the five proximal phalanges of the digits and at their other ends with the carpus in a manner already pointed out. Pollex nietacarj)al is very con- siderably shorter than any of the others; index and minimus metacarpals ^ In describing this l>one as the scaphoid, the fact is known to me tliat among rodents there are many wherein the scaphoid and lunar unite to form a single hone; and further that a special ossicle, which has been described as occurring on the radical side of the wrist, is of very considerable size in Gastw. It has also been said that in the beaver the scaphoid and lunar fuse to form one bone. Xotwithstanding these statements it is contended here that the scaphoid is present in Cynocephalus, though embryologj’ may disprove it, and two centers of ossification may be shown to exist in the bone here described as semilunar.