File:Caldwell05.jpg

PLATE 30. Sections through Ornithorhynchus, Echidna and Phascolarctos

Fig. 1. Ornithorhynchus. - Small portion of a section through the segmenting ovum, taken from the open end of the Fallopian tube, measuring 2.6 mm. in diameter : ch, pro-albumen ; vm, vitelline membrane.

Fig. 2. Echidna. - Small portion of a section through the segmenting ovum taken from the uterus, and measuring G mm. in diameter : sh, shell ; alb, albumen ; vm, vitelline membrane ; ma, coagulum ; bl, blastopore ; ep, epiblast ; hy, hypoblast.

Fig. 3. Ornithorhynchus. - Small portion of a section through the segmenting ovum taken from the uterus, and measuring 6 mm. in diameter : sh, base of shell ; sh₁, middle layer of ditto ; sh₂, papillae of ditto.

Fig. 4. Echidna. - Small portion of a section through the blastodermic vesicle, taken from the uterus, and measuring 9 mm. in diameter : sh₂ , cones derived from papilke of previous stage.

Fig. 5. Phascolarctos cinereus. - The 17th section of a vertical longitudinal series of 35 sections through the segmenting ovum, containing 2 nuclei, taken from the uterus, and measuring 0.17 mm. in diameter : sh, shell membrane; fe, cells of follicular epithelium ; alb, albumen ; ch, pro-albumen ; vm, vitelline membrane ; y t , protoplasm, with finest yolk granules ; y₂, white yolk ; n, nucleus of smaller segmentation area ; n₂, nucleus of larger segmentation area.

Fig. 6. Phascolarctos. - From uterus, 0.28 mm. in diameter, stage of 4 nuclei : sh, shell ; ch, pro-albumen ; alb, albumen ; vm, vitelline membrane.

Fig. 7. Phascolarctos. - From uterus, 0.31 mm. in diameter; lettering as in fig. G.

Fig. 8. Hypsiprymnus. - From uterus, 0.4 mm. in diameter: sh, shell membrane; vm, vitelline membrane ; um, coagulum ; bl, blastopore ; ep, epiblast ; hy, hypoblast. (Cf. fig. 2.)

Zeiss, oc. 2, obj. 1/18 homogen. : cam. luc.

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Links: plate 31 bw | plate 31

Reference

Caldwell WH. The Embryology of Monotremata and Marsupialia Part I. (1887) Phil. Trans. Roy. Soc 178 B.

Cite this page: Hill, M.A. (2024, April 19) Embryology Caldwell05.jpg. Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/File:Caldwell05.jpg

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