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 (p s) 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. 3466, 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 representeil 

 in fig. 1 tab. 8 of C. G. Carus's ' Tabulae Anatomiam Comparativam lllustrantes.' 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, 'Traite des Accoachements,' 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 Deve- 

 loppement des Corps Organise'es,' that I herewith append them : — " Enfin, la portion utero-placeniaire de la 

 rauqueuse uterine qui n'est pas entraiuee par le placenta lors de 1' accouchement n'est jamais caduque. et c'est a 

 tort qu'on lui donne ce nom, en ajoutant comme epithete les adjectifs serotine, interuUro-placentaire, &c. Elle 

 persiste toujours, et ne fait que diminuer peu-a-peu d'epaisseur jusqu'a ce que son niveau ait atteint celui de la 

 muqueuse qui se regenere. II est toutefois des femmes chez lesquelles la muqueuse reste, pendant plusieurs ann&s 

 aprfes r accouchement, plus epaisse 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 serotine s'exfolie et 

 s'elimine pendant la duree des lochies." The appearance faithfully reproduced, but left without explanation, by 

 M. Coste, which these views enable us to understand, will be found pi. 1 a, fig. 3. In his description we read, 

 " Tache rougeatre que presentait la muqueuse uterine, tout le reste de son etendue etaut exsangue." It is situ- 

 ated on the posterior wall, near the entrance of the left Fallopian tube of a uterus "d'une femme, mere de plu- 

 sieurs enfants, morte empoisonnee quelques jours aprcs 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. 



