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.

    12/72 (page 148)
    in the Mammalia, they are so intimately associated with the mandibles in the skull among all higher mammals and have been so extensively employed in the matter of classification, that to entirely ignore them in any general work upon the osteology of an animal belonging to that class would be considered an almost unpardonable oversight. Anatomists have by no means neglected the dental armature of Cynoceplialm and we meet with accounts of it in a number of works on comparative anatomy. Here, however, reference \\dll be made to only two authorities, Owen and Flower. Owen and Flower agree on the dental formula of Cynocephalus and, as given in their works, it agrees with all three of the specimens at hand, ikccording to Owen the dental formula of the genus is: .2.2 1.1 ^3.3’ ^ 1.1’^^ 2.2 3.3 »J-g=34. Owen also states that— The two anterior incisors of the upper jaw are separated by a wide interspace. In the Philippine Colugo they are very small, with simple sub-bilobed crowns; but in the common Colugo (Lemur volans Linn.; Galcopithecus Temminckii Wat.) their crown is an expanded plate with three or four tubercles; the second upper incisor presents the peculiarity of an insertion by two fangs in both species of Galeoplthecus?^ In the lower jaw the crowns of the first two incisors (i), present the form of a comb, and are in this respect unique in the class Mammalia. Figure 249 [Owen’s figure] shows a section of one of these teeth magnified. Tliis singular form of tooth is produced by the deeper e.xtension of the marginal notches on the crown, analogous to those on the edge of the new-formed human incisor, and those of certain slirews, the notches being more mpnerous as well as deeper. Each of these broad pectinated teeth is implanted by a single conical fang, and is excavated by a pulp cavity, which divides into as many canals as there are divisions of the crown, one being continued up the center of each to within a short distance of its apical extremity. The medullary canal or branch of the pulp cavity is shown in some of the divisions of the crown, (at p). Each divi- sion has its proper investment of enamel, (e), which substance is continued for a short distance upon the common base. The deciduous teeth appear not to cut tlie gum before birth, as they do in the true Bats. In a foetus GaJeopithecus Temminckii, with a head one inch and a half in length, I found the calcification of the first incisor just commenced in the closed alveolus, the second incisor and tlie rest represented by the vascular uncalcified matrices. The upper milk teeth consist of two incisors, a canine and two molars, which latter are displaced and succeeded by the two premolars. The deciduous teeth are six in number in the lower jaw, the incisors being pectinated, but much smaller than their successors. The true molars are developed and in place before the deciduous teeth are shed. “Anatomy of Vertebrates (1866), 3, 311-313. “ If we rely upon this diagnosis based upon the teeth, the specimens here being studied are certainly not C. volans; but that would not prove them all to be C. phUippinensis, as there may be other species having the two anterior incisors of the superior mandible like it.—R. W. S.