PLACENTAL STRUCTURES OF THE TENREC. 303 
specimens of their placental structures (which 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 ‘ Tabule 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 Manis shows it to be from the placenta 
of all the Carnivora, Rodentia, Insectivora, Chiroptera, and Simiade 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 placentz 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 placentz of the Elephant and the Hyraz, we are 
enabled to make one general description of the placentz of all the Unguiculata of 
Linnzus, 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 Hitheils 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 fcetus are so interblended with the 
vascular villi and folds of the foetal parts of the membrane, that in parturition they are 
1 Professor Breschet’s words are ,J. ¢. p- 461), “S’il ne s’est glissé aucune erreur dans V’histoire de la fait 
anatomique, il faut avouer que la loi que j’établissais de l’existence d’un double placenta dans I’ceuf des Singes 
de l’ancien continent, et d’un seul placenta dans celui des Singes d’Amérique, n’est pas exacte ou qu'elle souffre 
des exceptions. Le mieux serait peut-étre d’attendre que de nouvelles observations vinssent éclaircir 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 figured the two separate discoid placentz in the small South-American 
Squirrel-Monkey (Callithrix sciureus, Kuhl), in the Green Monkey (Cercopithecus sabeus, Desm.), and in 
the Long-nosed Monkey (Semnopithecus nasicus).’’ (Linn. Soc. Proc. 1857, p. 17, note.) 
* Cited by Professor Huxley, ‘ Lectures,’ p. 112. 
3 Cazeau, J. c. p. 191. 
“ Froriep, ‘ Notizen,’ J. c., October 1835. Weber refers here to a memoir of his own published 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. 
