V.—Observations on Marsupials in the Royal Scottish Museum, with special reference to the Fœtal Material

Abstract

Synopsis:A Critical survey is given of the spirit-preserved material of Marsupialia in the Royal Scottish Museum, with special reference to the fœtal stages.Of the crab-eating opossum, 12 mm., 16 mm., 20 mm., 30 mm. and 70 mm. stage pouch-embryos are discussed in detail, and compared with stages already known forD. marswpialis virginianus. A similar series ofDasyurus quoll, varying from 12·2 mm. to 34 mm., is considered, followed by notes on adults of some of the less well-known Dasyuridæ. Three pouch stages are studied in Peramelidæ and comparison made with data in the literature. In the Phalangeridæ fœtal stages ofPseudocheirus lanuginosus, Schoinobates volans, Trichosurus vulpeculaandAcrobates pygmœusare included.Macropodidœare represented byMacropus robustusstages ranging from 16 mm. (3·4 weeks old) to 138·7 mm.