



COMrARUOH W THE AXHEXE* OF THE IR'MAN rOTTCB WITH TUOCK OF ANIMALS. 



human f.i tii*. like that of the domesticated mammal*, u enveloped bv an amnion 

 atl rAorioN, which an> p lu-mlly identical in disposition with thoae already de*- 

 lAilieal rvmc/e mibmiU to the same change a* in the Mare, becoming to cj< 

 atrophied that scarcely any truce* of it can be found at birth. It U impossible to 

 isolate the amnion from the inn. -r face of the chorion; ao that tome anatomists only 

 admit its pretence by analogy with what u observed in animal*. 



Pig. t A 



DlAORAM OF AX KARI.V HTM AX OV1 M, 

 Stiouiv. Mil. AMMOX IX PROCm OF 

 FORMATION, AXD THE ALLAXTOIS BBOIX- 

 API'KAR. 



a, Chorion ; 6, Vitlline maw, surrounded by 

 the blattodennic vesicle ; c, Kmbryo ; d, <,/. 

 KiternAl and internal fold* of the m?rou* 

 layer, forming the aninino ; g, Incipient 

 alUotou. 



DIAGRAM OP A IICMAX OFfM 19 CJBOOKO 

 MUXTII, SHOW : ' OMPLETIOX OF 



MIK SAC OF TH) v !' A F0R- 



MIKR DCVELOPMEirr OF THE ALLAXTOU. 



cil, Smooth portion of the chorion; 

 villous portion; *, k, tUongaUd v 

 lecting into placenta; 6, Vitelline. or um- 

 bilical vesicle ; c, Embryo; /, Amnion, inner 

 layer; A, Its outer layer coalescing with 

 the chorion. 



The vmbilieal rord often nothing particular. The placenta U circular ; its diameter 

 at the termination of pregnancy ix>ing fmm 5 to S inrlien. and its thickneM from 1 to li 

 inchea. There in distinguiBhed the /a/a/ j>/aren/<i, in the midat of which tin- tun 

 cord arrives ; and the mattrnal placenta, whose villoaitiea dovetail with thoee of the 



' 



'I'hi' iiiM-rtion of the placenta take* place towards the fund us of the otenu, near 

 of the Fallopian tubes. NVlu -n there are more than one foetus, there are a corresponding 

 number of placentas. 



Independently of those annexes, which are the same in all, there is described for the 

 human foetus a special envi ! | . < \t. rnal to the chorion ; this u the mtml>ra*a focidua. 

 This is formed by the hyparBOphied mucous membrane, which i.- ilu)>l>st UMU; 

 ovum, when the latter is lodged in th. in. rui. cuvity. (' :.~. .|ii< sitlv . then- results the 

 division of the decidua into two parts : the true decitlua (deridua r<r.i) hi<-h .-..vera the 

 ntema, and the rrJUHed dtfidua (dteiilua rtfltjra) which t n\. l|w the chorion. These 

 present the character* of the hy|x-rtri>lu<tl uterine mucous membrane. 



