. The cyclopædia of anatomy and physiology. Anatomy; Physiology; Zoology. Fig. Uterine Ovum, magnified and dissected, Ornithorhynchus. (Owen, Phil. Trans. 1834.) curling inwards like the coat of an hydatid. This membrane is of a dull greyish colour, inclining to brown, slightly transparent, and more polished upon its inner than upon its outer surface : it resembles the cortical mem- brane of the ovum of the Salamander, but is of a more delicate texture. The fluid contents occupied the space between the cortical and vitelline membranes, a situation analogous to that of the albumen in the
. The cyclopædia of anatomy and physiology. Anatomy; Physiology; Zoology. Fig. Uterine Ovum, magnified and dissected, Ornithorhynchus. (Owen, Phil. Trans. 1834.) curling inwards like the coat of an hydatid. This membrane is of a dull greyish colour, inclining to brown, slightly transparent, and more polished upon its inner than upon its outer surface : it resembles the cortical mem- brane of the ovum of the Salamander, but is of a more delicate texture. The fluid contents occupied the space between the cortical and vitelline membranes, a situation analogous to that of the albumen in the egg of the fowl, but had not become coagulated by the action of the spirit in which it had been so long im- mersed. The yellow matter, or yolk, was seen to be invested by its proper capsule (fig. 193, 6), which, when reflected under the microscope, was found to consist of an extremely thin, smooth, and transparent outer layer, which I regard as the membrana vitelli (Jig. 194, «), with a thicker granular membrane immediately lining it, analogous to the blastoderma or ger- minative stratum (fig. 194, b). The contents of the above investments, or substance of the yolk, consisted of innume- rable minute opaque granules, similar in size and regularity of form to those contained in the ovarian follicles; and with these gra- nules were mingled larger transparent glo- _ bules of oil. There wasPfon ^** vitelline mem- .1 i-i. orane and germinal stra- not the slightest trace tum> Ornithorhynchu,. of chalazae attached to (Owen,) the vitelline membrane, as from analogy we might have expected, had the ovum been destined to have been perfected by incubation. I was unable to detect any rudiments of the embryo : an opaque streak was discernible on one part of the yolk, but not sufficiently definite to be satisfactorily re- cognised as a cicatricula; it is indeed, proba- ble, from the observation of Lieutenant Maule,* that the ova attain a greater size by the im- bibition of
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