AND THOSE OF CERTAIN OTHER MAMMALIA. Ill 



connected with the uterine tissues by blood-vessels, B V, and by tags or fimbriae, 

 D S", which pass from its periphery to become continuous with the uterine mucous 

 membrane. From its concave surface there is a downward growth, D S', which 

 embraced the upgrowth, P 1/ (the 'Kern' of Bischoff), and which ends in two 

 processes, the one, D R, being the remnant of the decidua reflexa, the other con- 

 nected the deciduous serotina with the placenta. The persistent non-deciduous 

 serotina is a very thin layer, not separable as a distinct stratum to the naked eye 

 from the circular muscular coat, C M, but it contains uterine glands. A wide 

 interval, partly artificial, and containing many blood-vessels, B V, separates the 

 circular from the longitudinal muscular coat, L M. The mesometrium, M, is 

 attached to the convex border of the figure. 



Fig. 4. Afterbirth of Rabbit (Lepus cuniculus), showing the prolongations of the 

 decidua serotina at either extremity of the structure, and their continuity with the 

 uterine mucous membrane, U M. The placenta is obscurely seen to be made up 

 of several (two or more) lobes, which are clamped together by a centrally con- 

 stricted decidua serotina, D S, the constriction corresponding to the interval be- 

 tween the main divisions of the placenta. The decidua serotina has its long axis 

 at right angles to that of the uterine cornu, to the mesometrial border of which it 

 is, in this as in every other Rodent, attached. From either end a process is pro- 

 longed beyond the placental area to become continuous with the uterine mucous 

 membrane on the free half of the tube, portions of which are drawn at U M. 

 Fringing the lateral borders of the decidua serotina, along which the uterine 

 mucous parapet was continuous with it, and passing underneath its two prolonga- 

 tions, D S", is seen the decidua reflexa, which is rudimentary in the Leporidae. 



Fig. 5. Part of placenta, deciduae, and uterine walls of Pig-tailed Monkey (Macacus 

 nemestrinu8). The placenta, P L, has been artificially separated from the utero- 

 placental area, and is kept in connexion with the uterus by a pointed process 

 abutting upon its uterine aspect and consisting of both decidua vera and of per- 

 sistent and deciduous serotinae. A thin lamina of membrane, D S, is seen in 

 the intervals between the placenta and the utero-placental area, being one part of 

 the decidua serotina, tougher, more coherent, and more separable in this simious 

 than in the human placenta. The persistent serotina, P S, is loosely reticular, but 

 limited towards the placenta by a smooth horizontally lying membrane, which 

 would probably have been deciduous. The decidua reflexa, D R, is represented by 

 a layer on the chorion, CH; it is separated by a wide interval from the non- 

 placental uterine mucous membrane, U M, which might perhaps not have been 

 deciduous. ' Decidua- For tsatze ' are well seen in the section of this placenta as in 

 the human placenta at six months. 



