PLACENTAL STRUCTURES OF THE TENREC. 295 
lamina of this tissue passed to be connected with the convex surface of the deciduous 
serotina, about an eighth of an inch from its free edge, i. e. the thickened peripheral rim 
already spoken of. The non-deciduous serotina (ps) resembles the homologous struc- 
ture in the human uterus in histological characters, but, so far as the naked eye is con- 
cerned, it differs widely from it, inasmuch as the deciduous serotina in the contracted 
human uterus forms a more or less elevated mass projecting into the cavity of the uterus, 
and not a laterally appended diverticular mass as in the Rat. It is interesting to 
remark that the deciduous serotina in Man does form a mass of such size as to have 
caused it to be mistaken! for a morbidly adherent placenta—an error involving serious 
consequences, but not likely to be committed by persons who by actual inspections, 
such as the one here recorded, of the changes undergone by the homologous structures 
in lower animals have vividly present to their mind the fact, which is indeed enucleable 
a@ priori, that the non-deciduous serotina of an emptied and contracting uterus must 
have different positions, relations, and proportions from those which it occupied when 
spread over the utero-placental area of a gravid and yet distended organ®. 
A person who, like myself, is not always able to compare the specimens in the Hun- 
terian Collection with the descriptions given of them in the catalogues which are 
accessible at a distance from London, would, from the description of Prep. 8466, vol. v. 
Physiological Series, be led to suppose, like myself, that the condition of parts there 
described is the same as that represented in my figure 8, and not that represented 
in fig. 1 tab. 8 of C. G. Carus’s ‘ Tabula Anatomiam Comparativam Illustrantes.’ I 
have, however, since the appearance in Professor Huxley’s ‘ Elements of Comparative 
Anatomy’ (p. 107) of a sketch of the principal points of this paper, satisfied myself, 
by an examination of the specimen no. 3466, Hunterian Museum, that I was wrong in 
supposing the preparation to have been wrongly described as a Rat’s. uterus ‘‘at an 
 Cazeau, ‘ Traité des Accouchements,’ 1856, p. 500. 
? The following words from M. Robin’s Memoir (p. 137) are so important in themselves, and besides this they 
furnish such a valuable explanation of an appearance left unexplained in M. Coste’s valuable ‘ Histoire du Déve- 
loppement des Corps Organis¢es,’ that I herewith append them :—“ Enfin, la portion utéro-placentaire de la 
muqueuse utérine qui n’est pas entrainée par le placenta lors de l’accouchement n’est jamais caduque, et c’est d 
tort qu’on lui donne ce nom, en ajoutant comme épithéte les adjectifs sérotine, intérutéro-placentaire, &e. Elle 
persiste toujours, et ne fait que diminuer peu-d-peu d’épaisseur jusqu’a ce que son niveau ait atteint celui de la 
muqueuse qui se régénére. Il est toutefois des femmes chez lesquelles la muqueuse reste, pendant plusieurs années 
apres l’'accouchement, plus épaisse et plus saillante dans cet endroit qu’ailleurs.” M. Robin says, in a note of a 
previous paper of his, treating of this point, “ J’admettais done a tort, avec les autres, que la scrotine s’exfolie et 
s’élimine pendant la durée des lochies.”’ The appearance faithfully reproduced, but left without explanation, by 
M. Coste, which these views enable us to understand, will be found pl. 1 a, fig. 3. In his description we read, 
“Tache rougedtre que présentait la muqueuse utérine, tout le reste de son étendue ¢tant exsangue.” It is situ- 
ated on the posterior wall, near the entrance of the left Fallopian tube of a uterus “d’une femme, mire de plu- 
sieurs enfants, morte empoisonnée quelques jours apres la menstruation.” There can be little doubt, I apprehend, 
that this vascular areola indicates the gradually diminishing non-deciduous serotina of, probably, the last 
pregnancy. 
