File:On the anatomy of vertebrates (electronic resource) (1866) (14750987325).jpg

Identifier: b20416039_003 (find matches)
Title: On the anatomy of vertebrates (electronic resource)
Year: 1866 (1860s)
Authors: Owen, Richard, 1804-1892
Subjects: Anatomy, Comparative Vertebrates Fishes Reptiles Mammals Birds
Publisher: London : Longmans, Green
Contributing Library: Wellcome Library
Digitizing Sponsor: Wellcome Library

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s. The uteri are fusi-form, relatively longerin multiparous, fig. 537,than in uniparous, fig.538, species. The mus-cular coat is of moderatethickness, exceeded bythe innermost, owing tothe abundance of lax areolar and vascular tissue which supportsthe smooth delicate lining membrane, which is usually throwninto many folds. Each uterus communicates with its own vaginaby a valvular prominence, or 6 os tineas. The vaginae are ofremarkable length in Marsupialia, and folded or otherwise deve-loped, so as to adapt these passages to detain the fetus after ithas been expelled from the uterus for a longer period than inother Mammalia. These complications vary considerably in the different mar-supial genera. On a comparison of the female organs in Didel-phjs dorsigera, Petauruspygmceus, Petaurus taguanoides,Dasyurusviverrinus, Didelphys Virginiana, Macropus major^ and Hypsi-prymnus murinus, I find that the relative capacity which theuteri bear to the vagina? diminishes in the order in which the
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682 ANATOMY OF VERTEBRATES. 537 above-named species follow, while the size of the external pouchincreases in the same ratio. In Didelphys dorsigera the uteri, fig. 537, c, c, rather exceedthe unfolded vaginas in length. Each vaginal tube, e, e, afterembracing the os tineas, d, is immediately continued upward andoutward, then bends downward and inward, and, after a second bend upward, descends bythe side of the opposite tubeto terminate parallel wTiththe urethra, h, in the com-mon or urogenital passage,f.1 In Petaurus the vagi-nas, when unfolded, are alittle longer than the uteri:they descend close togetherhalf-way toward the uroge-nital passage, and thereterminate blindly withoutintercommunication. Fromthe upper part of these culs-de-sac the vaginas are con-tinued upward and outward,forming a curve, like thehandles of a vase, thendescend, converge, and ter-minate close together, as inthe preceding example.2 InDasyurus viverrinus andDidelphys Virginiana the mesial culs-de-sac of the va

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