. The Australian zoologist. Zoology; Zoology; Zoology. 150 EXTERNAL CHARACTERS OF SOME AUSTRALIAN Fig. 8. Phascolarctos cinereus. Palmar surface of the left manus at stage C (54 mm.). medial apices. Pocock (13) has suggested that the pad at the base of the second digit represents the "first or external element of the plantar pad," that is, is the first interdigital. The occurrence of the distal pads digitally and not interdigitally is atypical and may be a consequence of the wide separation of the second and third digits resulting in the second inter- digital migrating l
. The Australian zoologist. Zoology; Zoology; Zoology. 150 EXTERNAL CHARACTERS OF SOME AUSTRALIAN Fig. 8. Phascolarctos cinereus. Palmar surface of the left manus at stage C (54 mm.). medial apices. Pocock (13) has suggested that the pad at the base of the second digit represents the "first or external element of the plantar pad," that is, is the first interdigital. The occurrence of the distal pads digitally and not interdigitally is atypical and may be a consequence of the wide separation of the second and third digits resulting in the second inter- digital migrating laterally and causing a similar shift in the third and fourth; if this has occurred there seems no reason why the first inter- digital pad should move to the base of the second digit. Specimens A and B are not of assistance in making more specific suggestions for clarification of the nomenclature. It should be emphasized that the absence of an epidermal ridge pattern on the pads in question, taken in conjunction with their unusual position, throws some doubt on their claim to be regarded as true volar pads. The Pes.—The relatively great size of the syndactylous digits is seen as early as stage A; in fact, they are as long or longer than the fourth digit; Dankmeijer (14) has figured this condition in a 60 mm. embryo. In all stages the plantar pads are too feebly differentiated for exact descrip- tion. The Pouch.—Five of the eight specimens which comprise the series are females and provide an interesting picture of the early development of the pouch. The youngest female is C (54 mm.) in which the pouch is a deep longitudinal groove the lips of which are united anteriorly but separated posteriorly so that the groove may be said to be open posteriorly; it is (13) Pocock, Proc. Zool. Soc. Lond., 1921, p. 601. (14) Dankmeijer, Gegen. Morph. Jahrb., 82, 1938, p. 303, fig. Please note that these images are extracted from scanned page images that may have been digitally enhanced
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectzoology, bookyear1914
