. On the anatomy of vertebrates [electronic resource] . the latter are attracted to thecontiguous surfaces, some to thatof the ovisac, which thus becomeslined by a thicker layer of cells,others to the ovum, accumulatingaround it. With the enlarge-ment of the ovisac, the ( stromaovarii condenses around its deli-cate membrane, fig. , b, to formthe ( theca folliculi of vascular covering of the Formation of the ovisac, Dog. cclxi. .-, • i i ovisac, ib a, with the properwall, ib. b, constitutes the c Graafian vesicle or follicle. Thestratum of nucleate cells lining the ovisac is terme
. On the anatomy of vertebrates [electronic resource] . the latter are attracted to thecontiguous surfaces, some to thatof the ovisac, which thus becomeslined by a thicker layer of cells,others to the ovum, accumulatingaround it. With the enlarge-ment of the ovisac, the ( stromaovarii condenses around its deli-cate membrane, fig. , b, to formthe ( theca folliculi of vascular covering of the Formation of the ovisac, Dog. cclxi. .-, • i i ovisac, ib a, with the properwall, ib. b, constitutes the c Graafian vesicle or follicle. Thestratum of nucleate cells lining the ovisac is termed e membrana voce ovuli semper usus sum, quia vesicula Graafiana ipsa ovum refert, respeetoovario, ex ovulo autem, fit ovum fetale. . Ex quo concludo: quo diutius in corporematenio fetus foventur, eo magis jam jprimitus exculta videtur ovi vesicula innata, quaein mammalibus eo pervenit ut omnes ovi virtutcs in sese recipiat ct reliqucs ovi pa?tesparvi momenti extranece quasi fiant. ccxlix. p. 33. [The italics are V. Baers.]1 ccl. ccli. OVIPONT IN MAMMALIA. 711 556 granulosa, those which surround the ovum itself form the e pro-ligerous disc/ ib. e, and the mass of cells thereto adhering is thei cumulus. The ( hyalinion, or proper tunic of the ovum, thickensinto the clear substance called ( zonapellucida, The cells immediatelyaround the ovum, as it ripens, elongateand become pyriforin, with the pointedend attached to the i zona: those ofthe cumulus diverge irregularly into thefluid intervening between them and thee membrana granulosa of the ovisac :but the four groups, defined by Barry2as (retinacula,5 ib. d, and fig. 559,2, may be an exceptional disposition. The ripe ovarian ovum, freed fromits cellular precipitate, fig. 557, is inclosed in the thick trans-parent structureless i hyalinion, a: its vitelline contents areopaque through the abundance of granular yolk-substance, b :
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