Tin: m:r.\i. MKMHUANKS 01 MAX. 



245 



dg 



di 



(the allantoi.x). :.IH! conduct* the allantoic I>1>'..; from the 



pelvic portion nl' llif intestine to tin- chorion. 



Thi> cord is ;i ch.-iracteri-t ic -i met ur- fur the liuinan embryo, the 

 si^nilicance of which is still in dispute. KOU.IKKK ami Hi- 

 i:iven someuhat dill'eivnt explanation- of it. KO|.UKI:K brin-- ih" 

 coid into relation with the development of the allantois. l|i> maki-> 

 the fundament of this important embryonie appendage ari-e. as in 

 other Mammals, from the hind rui of the eml.ryo, ami approach the 

 scro-a as a thick va-cular connec e i:i-outh lineduit h a nario\\, 



slmri epithelial 

 tulio. \\ithont 

 previously de- 

 veloping in>il(^ 

 it>elf a lar^e 

 epithelial SBC. 

 He also main- 

 tains that the 

 connect! ve- 

 tisMio part of 

 the short allan- 

 toic cord, or 

 belly-s t a 1 k. 

 :ro\\> arouml 

 on the whole 

 inner side of 

 the serosa, and 

 into the epi- 

 thelial villi. 



His regards 

 a s u n w ar- 

 rant ed "the 



a -sumption, in opposition to the actual state of atlairs. that the 

 human emhrvo at first separates it -elf from the part of the bla>t>- 

 dermic voide \\hich is employed for the chorion, and sul>-e|uently 

 unites with it a^ain by means of the fundament of the allantois." 

 He does not admit that the fundament of the emhryo in Man is 

 ever wholly con-t ricted oil' from the chorion. as in the remaining 

 Mammals, and he rei-< Anises in the belly-stalk "the bridge of 

 connection between the fundament of the embryo and the 

 chorionic part of the original lla>todermic v.-icle. which has 

 never been severed." According to him. the allantois in the 



V 



Fig. 141. -Human embryo with yolk-sac, amnion, and belly-stalk of 



15 to 18 days, aftet COSTE, from His ("Menschlidif Kiul>r\onen"). 



i]iu-\\li;it the posterior ml of the \><>.\\ in cora- 



l>:iris<m with the nriiriii;il ti-ure. in on't-r to Lrini: int.) \ie\v the 



ri^'ht side of the end of the body, the left side being represented 



in COSTF/S fig. 4. The chorion is detached at am 1 , am, Anmion ; 



am\ the point of attachment of the ainnion to the chorion drawn 



out to a tip; bit, lx-1 Mb, tail-i-ml ; us, jtriinitive seg- 



ment; dy, vitelline blood-vessels; in, yolk-sac: /<. h<.n 



.! aii-h. 



