96 ON THE PLACENTAL STRUCTURES OF THE TENREC 



and foetal blood- vascular systems than would have been due to a 

 similar investigation of it in the recent state. I am not, however, 

 myself inclined to think that the lapse of time has made any differ- 

 ence of consequence in the appearances in question. Approxima- 

 tions, on the other hand, to the sinus arrangement of maternal 

 intra-placental vessels have been noticed by Eschricht (1. c. p. 24) 

 as existing in the cat; and Kolliker (1. c. pp. 163, 170) speaks of 

 the f colossal capillaries' \'" wide, of the dog's placenta, as forming, 

 in contradistinction to the ordinary capillaries of the homologous 

 parts in the rabbit, the ruminants, and the pig, a transition to- 

 wards the arrangement which, in the previous sentence, he cha- 

 racterises as exclusively human \ 



It is well to put on record the fact that upon yet a fourth 

 point of supposed difference between the simious and the human 

 placenta considerable weight has been laid, which close examination 

 has shown it would not bear. This point was the persistence of 

 the umbilical vesicle ; and Rudolphi 2 speaks emphatically of its 

 supposed disappearance at the third month in the human foetus 

 as sharply differentiating its foetal structures from those of Mycetes, 

 which, in other points, it so closely coincides with. This statement 

 looks strange by the side of such a title to a recent monograph 3 

 as the following : ' Das Nabelblaschen ein constantes Gebilde in 

 den Nachgeburt des ausgetragenes Kindes' (The umbilical Vesicle 

 a constant structure in the After-birth of the Child at full time '), 

 or of a statement to the same effect as the heading of this paper 

 of Dr. Schultze's, which is made by Breschet 4 in his already 

 cited memoir. 



Before leaving the subject of the simious placenta, it may be 

 well to state that the last-named author is inclined to suspect that 

 further investigation will show that a naked-eye difference of 

 arrangement distinguishes, as do many other points of the like 

 character, the Old- World from the New-World monkeys. This 

 point of difference is the possession by the New- World of a uni- 



1 [The Editor in his memoir on the Placentation of the Apes (Phil. Trans. 1878, pp. 

 537, 555) has now established the presence of an intra-placental sinus-system in the ape.] 



2 'Abhandlungen Berlin Akad. Phys. Klass.' 1828. 'Bis hierher alles also mensch- 

 lich ; aber nun die grosste Abweichung zwar nicht der absoluten aber der relativen 

 Zeit nach wem man das Nabelblaschen betrachtet.' 



3 Von Dr. Bernhard Sigismund Schultze, Professor der Geburtshiilfe in Jena ; 

 Leipsic, 1861. 4 I.e. p. 470. 



