1878.] Prof. TV. Turner on the Placentation of the Apes. 271 



Dielectric. Specific Inductive Capacity. 



* Bisulphide of carbon 1*4474 



Chance's optical ( Double extra dense flint .... 1*6840 



glass. I Extra dense flint 1*6727 



Slabs nearly 1 inch j Light flint V6677 



thick. v Hard crown , „ . . 1*6872 



Common plate glass,] x -, oqoo -i 



2 slabs, each 1 inch > ^ } Mean. . . . 1*6918 



thick, about. J 



The author suggests that the fact that all his results are much lower 

 than those obtained by previous experimenters may perhaps be ex- 

 plained on a supposition that the specific inductive capacity of dielec- 

 trics increases from an inferior to a superior limit during the first 

 small fraction of a second after the commencement of the electrifica- 

 tion. He discusses this question at some length in his paper. f 



An expression of thanks to Professor Maxwell, for his close super- 

 intendence of the work, concludes the paper. 



IY. " On the Placentation of the Apes, with a Comparison of the 

 Structure of their Placenta with that of the Human Fe- 

 male." By William Turner, M.B. Lond., F.R.S., Professor 

 of Anatomy in the University of Edinburgh. Received 

 March 11, 1878. 



(Abstract.) 



The introductory chapter of this memoir consists of a summary of 

 the observations of John Hunter, Rudolphi, Breschet, Owen, Huxley, 

 Rolleston, Ercolani, and Kondratowicz, on the form and structure of 

 the placenta in the apes. The author then gives a detailed description 

 of his dissection of the gravid uterus and placenta of a Macacus cyno- 

 molgus well advanced in pregnancy. He then enters into a detailed 

 comparison between the form and structure of the placenta in the ape 

 and that of the human female, in the course of which he records a 

 number of original observations on the structure of the human pla- 

 centa. Attention is more especially drawn to the comparative struc- 

 ture of the decidua vera and serotina ; to the prolongations of the 

 decidua serotina into the interior of the placenta; to the arrangement, 

 structure, and mode of origin of the intra- chorionic and sub- chorionic 

 cells ; to the arrangement of the arteries and veins of the placenta ; 



* I cannot vouch for the exact accuracy of this determination, as the method, of 

 experimenting on liquids is not yet quite perfected. 



f Note added April 7th. Compare Ayrton and Perry, on the " Yiscosity of Di- 

 electrics," read March 21, 1878. 



