![Phil and Alex on Twitter: "I prayed for more than just a gestational sac (even though that's all we would need to see). Yolk sac made its first glimmer of appearance! I Phil and Alex on Twitter: "I prayed for more than just a gestational sac (even though that's all we would need to see). Yolk sac made its first glimmer of appearance! I](https://pbs.twimg.com/media/EF19V6QWsAUDaFH.jpg)
Phil and Alex on Twitter: "I prayed for more than just a gestational sac (even though that's all we would need to see). Yolk sac made its first glimmer of appearance! I
![Elementary text-book of zoology. Yolk-sac. Embryo. miotic Cavity.. Yolk-sac. A, Stage of tbe Frog witb only small Yolk-sac ; B, Stage of the Skate ; ^, Stage of Developing Amnion ; Elementary text-book of zoology. Yolk-sac. Embryo. miotic Cavity.. Yolk-sac. A, Stage of tbe Frog witb only small Yolk-sac ; B, Stage of the Skate ; ^, Stage of Developing Amnion ;](https://c8.alamy.com/comp/RDGETW/elementary-text-book-of-zoology-yolk-sac-embryo-miotic-cavity-yolk-sac-a-stage-of-tbe-frog-witb-only-small-yolk-sac-b-stage-of-the-skate-stage-of-developing-amnion-d-stage-as-in-many-reptilia-the-amnion-and-serosa-are-not-completely-separated-cc-also-monotremata-e-a-typical-sauropsid-epiblast-is-represented-white-mesoblast-black-and-hypoblast-dotted-please-note-that-these-images-are-extracted-from-scanned-page-images-that-may-have-been-digitally-enhanced-for-readability-coloration-and-appearance-of-these-illustrations-may-not-perfectly-resemble-the-original-RDGETW.jpg)
Elementary text-book of zoology. Yolk-sac. Embryo. miotic Cavity.. Yolk-sac. A, Stage of tbe Frog witb only small Yolk-sac ; B, Stage of the Skate ; ^, Stage of Developing Amnion ;
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