98 ON THE PLACENTAL STRUCTURES OF THE TENREC 



The figure of the placenta of the sloth, which is given by Pro- 

 fessor C. G. Cams in his 'Tabulae Anatomiam Comparativam II- 

 lustrantes,' 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 l of the placenta of the Manis shows it to 

 be from the placenta of all the Carnivora, Rodentia, Insectivora, 

 Chiroptera, and Simiadae 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 con- 

 fidently as to the extent of intimacy with which the maternal arid 

 foetal blood-vessels are connected than the figures alluded to from 

 Professor Carus's work can do 2 . 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 3 ) maternal elements inextri- 

 cably 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 re- 

 productive organs. This, however, is but conjecture. It is of 

 more consequence to observe that, by Professor Huxley's exami- 

 nation of the placentae of the elephant and the hyrax, we are enabled 

 to make one general description of the placentae of all the Un- 

 guiculata of Linnaeus, deducting from them, provisionally, the Eden- 

 tata, and definitely Rhinoceros and Bidelphys. This general pro- 

 position we cannot give better than in the words of Weber, ad- 

 dressed, now nearly thirty years ago, to an association of German 

 naturalists and Physicians at Bonn 4 : — 



' Die gefassreiehen Zellen oder Falten oder anders gestalteten zur Verbindung vom 

 Mutter und Frucht dienende Organe des Uterus mit den gefassreiehen Zotten und 



Professor Breschet has described and figured the two separate discoid placentae in 

 the small South- American squirrel monkey (Callithrix sciureus, Kuhl), in the green 

 monkey (Cercopithecus sabaeus, Desm.), and in the long-nosed monkey (fiemno- 

 pithecus nasicus). (Linn. Soc. Proc. 1857, p. 17, note.) [The Editor has shown that the 

 placenta iu the Old- World Cynocephalus mormon is single. 'Phil. Trans.' 1878, p. 560.] 



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



2 [The Editor has since the above was published described the placenta of a two- 

 toed sloth, Cholopus hoffmanni ('Trans. Roy. Soc. Edinb.' 1873, vol. xxvii), and has 

 shown the maternal to be intimately mingled with the foetal structures.] 



3 Cazeau, I.e. p. 191. 



* Froriep, ' Notizen,' I.e., 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 Von 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. 



