PLACENTAL STRUCTURES OF THE TENREC. 303 



specimens of their placental structures (ivhich were, however, in both cases alike in a 

 bad state of preservation) Professor Breschet' was unable to satisfy himself that his rule 

 held good. 



The figure of the placenta of the Sloth, which is given by Professor C. G. Carus in 

 his 'Tabulae Anatomiam Comparativam Illustrantes,' pars 3, does not seem to me to 

 be so decidedly different from even the Human placenta, in its naked-eye bossy outlines, 

 as Dr. Sharpey's account'^ of the placenta of the Mam's shows it to be from the placenta 

 of all the Carnivora, Rodentia, Insectivora, Chiroptera, and Simiadse which have been 

 as yet examined. A well-injected or even a well-preserved pregnant uterus of a Sloth 

 would be most valuable, and would enable us to speak more confidently as to the 

 extent of intimacy with which the maternal and foetal blood-vessels are connected than 

 the figures alluded to from Professor Carus's work can do. Should the placenta of the 

 Sloth be found to bring away with it (as we know placentae to the full as cotyledonary 

 in general outline do^) maternal elements inextricably intermingled with its mass, the 

 structure of the placenta of the Manis might perhaps be explained as being an instance 

 of "correlation of growth" between aberrant tegumentary and reproductive organs 

 This, however, is but conjecture. It is of more consequence to observe that, by 

 Professor Huxley's examination of the placentae of the Elephant and the Hyrax, we are 

 enabled to make one general description of the placentae of all the Unguiculata of 

 Linnaeus, deducting from them, provisionally, the Edentata, and definitely Rhinoceros 

 and Didelphys. This general proposition we cannot give better than in the words of 

 Weber, addressed, now nearly thirty years ago, to an Association of German Naturalists 

 and Physicians at Bonn*. " Die gefassreichen Zellen oder Falten oder anders gestalteten 

 zur Verbindung vom Mutter und Frucht dienende Organe des Uterus mit den gefass- 

 reichen Zotten und Falten des Eitheils so verwachsen sind dass sie bei der Geburt vom 

 Uterus abgerissen werden." " The vascular cells or folds or otherwise shaped organs of 

 the uterus for the connexion of the mother and the foetus are so interblended with the 

 vascular villi and folds of the foetal parts of the membrane, that in parturition they are 



' Professor Breschet's words are {I. c. p. 461), " S'il ne s'est glisse aucune erreur dans rhistoire de la fait 

 anatomique, il faut avouer que la loi que j'ctablissais de 1' existence d'un double placenta dans I'oeuf des Singes 

 de I'ancien continent, et d'un seul placenta dans celui des Singes d'Amerique, n'est pas exacte ou qu'elle soufixe 

 des exceptions. Le mieux serait peut-etre d'attendre que de nouvelles observations yinssent eclaircir la question 

 et lever tous les doutes sur la pointe." The following account, therefore, which may apply, perhaps, to Professor 

 Breschet's labours, will nevertheless, I apprehend, give an incorrect impression of what his opinions are: — 

 " Professor Breschet has described and Bgured the two separate discoid placentse in the small South-American 

 Squirrel-Monkey {Callithinx sciureus, Kuhl), in the Green Monkey (Cercopithecus sabemes, Desm.), and in 

 the Long-nosed Monkey {Semnopithecus nasicus)." (Linn. Soc. Proc. 1857, p. 17, note.) 



' Cited by Professor Huxley, 'Lectures,' p. 112. 



' Cazeau, 2. c. p. 1 9 1 . 



* Froriep, 'Notizen,' I. c, October 183.5. Weber refers here to a memoir of his own pubhshed in 1832 in 

 Hildebrandt's ' Anatomie ' ; but he appears to have had no knowledge of V. Baer's now well known paper on the 

 same subject and to the same purpose, bearing date 1828. See Professor Huxley's 'Lectures,' p. 92. 



