100 ON CLASSIFICATION. 



I have italicised to look into the matter afresh, I have found that 

 the assertions made therein respecting the placenta of the Eat 

 are as completely contrary to fact as are those respecting the brain 

 of the apes which I have already cited from the same author. 



Figure 42 represents a section of the uterus, chorion, and 

 partially-injected placenta of a foetal Eat, one inch and a 

 quarter long, taken in a direction perpendicular to the long 

 axis of the uterine cornu. a is the mesometrium traversed by 

 a large uterine vein ; b is the wall of the uterus becoming 

 looser in texture and traversed by large venous channels in its 

 inner substance, c; d is a decidual layer of the uterus of a 

 cavernous structure, whence vascular processes are continued 

 towards the chorionic surface of the placenta. A large vein (i) 

 passes directly from the decidual layer (d), and the uterine 

 sinuses beneath it, to near the chorionic surface of the placenta, 

 beneath which it branches out horizontally. The chorion (/), 

 rendered vascular over its non-placental part by the ornpha- 

 lomeseraic vessels (&), only begins to exhibit villous processes 

 and folds at the point (g). These outermost villi appear to 

 me to be free; but, more internally, they become closely 

 connected with the upper surface of the placenta; and over 

 the central third of the foetal face of the placenta, the umbilical 

 vessels (I) ramify in a radiating fashion, and send prolongations 



observassein, initio tota mea de structura placental lnammalium unguiculatoruin 

 sententia labefacta est. Gliribus si ut ruminantibics pars uterina placentas in partu 

 non abstruderetur, mirum sane fuisset, etsi theoria de placentas structura in uni versum 

 eo nihil caperet detrimenti. Quum vero superficiem uterinam placentas lasvem 

 observassem, et idem de superficie ipsius uteri ei obversa nunc observarem, tota 

 theoria pasne refelli mihi videbatur, secundum quam alternatio quasdam utriusque 

 systematis adsit neccssr est. Attamen mox intellexi corpus illud uterinum non 

 ipsam partem uterinam placentas esse. Supra jam de vase majore centrali et 

 quinque minoribus circumstantibus sermo erat, quas placentas superficiem uterinam 

 transibant. Eadem vasajam in ipsius uteri superficie observavam et in apertoerat 

 riiiuificationem eorum in laminubis ipsius placentas fieri. Corpus uterinum trans- 

 cissum cellulasplurimas exhibuit, ni tailor, sanguinis coagulati nonnihil etiamtunc 

 continentes. Sic constructum eidem functioni inservire mihi videtur ac similes 

 uteri humani cellulas vel sinus venosi ; nee placentam murinam aliter a placenta 

 iVlina discrepare video nisi quod vasa uterina pauciora sed sat magna partem 

 uterinam intrant. Quibus observationibus ductus etiam glirioi placentas ex 



PASTE FCSTALI ET I'TERINA CADTJCA HAC ET ILLA LAMIXIEIS IXNTMEIUS ALTKKXAXTIBUS 



< ii.mpositas esse ])utabo donee melioribus observationibus refutatus fuero." 



