TJIE PLACENTATION OF PERAMELES. 441 



Fig. 15. — Section through the marginal portion of the allantoic placental 

 area (cf. with Fig. 7). X 150. 



Fig. 16. — Portion of the central region of the allantoic placental area 

 (cf. with Fig. 8). X 150. 



Fig. 17. — Portion of the allantoic placental area, showing the interlocking 

 of the allantoic capillaries {all. cap.) with the vascular ridges of the syncytium. 

 X 325. 



Fig. is. — Section passing through a gland opening in the allantoic placen- 

 tal area, occluded by an allantoic capillary {all. cap.). X 230. 



Figs. 19 and 20. — Portions of allantoic placental area, showing isolated 

 and greatly enlarged chorionic ectoderm cells {cli. ect'.). X 230. 



Fig. 21. — Portion of allantoic placental area, showing an isolated multi- 

 nuclear chorionic ectoderm cell {ch. ect'.) X 230. 



Fig. 22. — Horizontal section of allantoic placental area, to show the net- 

 work formed by the allantoic capillaries {all. cap.), x 225. 

 Fig. 23.— Section of allantoic stalk (cf. with Fig. 10). X 140. 



Fig. 24. — Section passing through the sinus terminalis {s. t.), and including 

 the adjacent portions of the vascular {vase, omph.) and bilaminar omphalo- 

 pleure {bil.omph.), together with the syncytium {ex.spi.) in contact therewith. 

 X 240. 



Stage E. 



Fig. 25. — Genital organs from the ventral aspect. The left uterus {I. ut.) 

 has been opened up, exposing the allantoic placental area {pi. a.), and the 

 allantoic stalk {all. s.) has been traced back into the median pseudo-vaginal 

 passage (»ie(^./).). bl. Bladder. /. (. Fallopian tube. r. u(. Right uterus. 

 u. s. Urino-genital strand, v. ceec. Vaginal cseca. x 2. 



Fig. 26. — Portion of the coriuni of the mucosa beneath the allantoic 

 placental area, showing the alterations in the connective tissue, uterine glands, 

 and blood-vessels. c. f. Hypertrophied interglandular connective tissue. 

 d. gl. Gland with its lumen occupied by the disorganised epithelium, m. v. 

 Vessel of corium with thickened walls, m. v'. Vessel with its lumen filled up 

 by the proliferated endothelium, m. v". Vessel with its lumen completely 

 obliterated. I. p'. Thickened tunica propria around the uterine glands, x 325. 



Fig. 27. — Portion of allantoic placental syncytium in section, to show 

 degenerative and absorptive change, p. leuc. Polynuclear leucocytes. */;. 

 Spaces in syncytial protoplasm, x 550. 



Fig. 28. — Section through the marginal portion of the allantoic placental 

 area (cf. with Figs. 7 and 15). all. mes. Outer (placental) wall of allantois. 

 sp. Spaces in syncytial protoplasm, syn. o. Lamellar outgrowth of the mar- 

 ginal portion of the placental syncytium, x 80. 



