302 PROFESSOR TURNER ON THE PLACENTATION OF THE SEALS. 
Figure 7, Intra-placental maternal trabecule, tr. At ep, ep the columnar epithelial covering is seen 
in situ; at ep’, ep’ partially shed. Elsewhere the epithelium has been entirely removed, 
so as to show the sub-epithelial tissue with its corpuscles, and the single capillary ¢, in 
each trabecula. x 200. 
Figure 8. Branch of a villus, V, with its terminal bud-like offshoots. The vascularity of the villus is 
shown in the upper part of the figure, whilst at the lower end its cellular structure is 
represented. x 200. 
Puatre XX. 
Figure 9. Portion of. placenta, Pl, of the Grey Seal partially dissected off the uterus. mm, the uterine 
mucosa forming the non-deciduous part of the serotina; folds of this membrane may be 
seen entering the sulci or primary fissures, s,s, between the convolutions of the placenta. 
The broader red lines on the exposed surface of the placenta are intended to represent the 
secondary fissures of the placenta, and the finer lines the tertiary fissures, by which it is 
subdivided into the ultimate lobules, /. mp, np, non-placental portions of the mucous 
membrane. Natural size. 
Figure 10. Surface view of the uterine mucosa forming the non-deciduous serotina. At e, e the broad 
ends of the columnar epithelium cells, still in situ, are represented. In the rest of the 
figure the epithelium has been removed. wv, larger trunks of the blood-vessels of the 
mucosa ; ¢, capillary network ; ct, corpusculated sub-epithelial connective tissue ; gl, por- 
tion of one of the utricular glands. x 250. 
Figure 11. Vertical section through the placental area of the mucosa of the Cat, described on p. 290. 
er, the layer of branching crypts; the epithelial lining of the crypts, ep, ep, and their highly 
corpusculated connective tissue walls, ct, ct, are represented ; gi, the glandular layer; 
the glands are seen in section, much less numerous than the crypts, and surrounded by 
connective tissue ; ms, the muscular coat. x Hartnack 3 obj. 4 Oc.; tube out. 
Figure 12. Horizontal section through the erypt layer of the same uterus. 7, cr, cavities of the crypts 
with their epithelial liming. At e¢ the epithelium covering the free surface of the walls of 
the crypts is seen; at e’ the walls are in section, and the sub-epithelial connective tissue, 
with its corpuscles, ct, is exposed. x Hartnack 7 obj. 3 Oc.; tube out. 
Pratt XX]. 
Figure 13. Vertical section through the placenta, P/, of a Cat, about half time (p. 293). Ch, the 
chorion, the vessels of which are coloured blue, so that the blue network which passes 
through the thickness of the placenta represents the vessels of the villi; D, the decidua 
serotina ; the red-coloured vessels are the vessels of the uterine mucosa, which ascend in 
the walls of the crypts as far as the chorion, where they not unfrequently show consider- 
able dilatations,s. 6, bud-like terminal offshoot of a villus penetrating into the serotina ;_ 
ms, the muscular coat. x Hartnack 3 obj. 3 Oe. 
Figure 14. Horizontal section through the placenta of the same Cat. VV, transversely divided sinuous 
villi, the capillaries in which are coloured blue; J, J, lamin of uterine mucosa, forming 
the walls of the crypts. The red colour represents maternal vessels, as in figure 13. 
Figure 15. Villi, V, with a portion of the chorion, ch, of the shed placenta of a Cat at full time; B,a 
terminal bud, such as in figure 13, b penetrates deeply into the serotina. x 40. 
Figure 16. Horizontal section through the placenta of a Fox (p. 297). V, the blue-coloured vessels 
of the foetal villi; mz, the transversely divided colossal maternal capillaries. 
Figure 17. Vertical section through the non-gravid uterine mucosa of a Bitch (p. 297). e, ends of 
columnar epithelial cells covering free surface of mucosa; g, tubular gland shown in its 
entire length ; g’, a tubular gland cut short. At a@ the continuity of an apparently short 
gland, with the deeper end of a tube, is shown. ct, interglandular connective tissue, with 
its corpuscles ; 0, arteries passing into the mucosa; ms, muscular coat. x 100. 
Figure 18. Horizontal section through the non-gravid uterine mucosa of a Bitch, near the free sur- 
face. The close relation which the glands have to each other is shown; also the small 
proportion of interglandular tissue, in which rounded cells, not unlike lymph or white 
blood corpuscles may be seen. x 100. 
Figure 19. Surface view of the non-gravid uterine mucosa of the Crested Seal (Cystophora cristata). 
At e the columnar epithelium is in situ, elsewhere it has been removed; g, mouth of a 
tubular gland. The capillary network of the mueosais coloured red. « 100. 

