352 



HUMAN UTERUS AND FCETAL APPENDAGES. 



that the coelom is entirely obliterated, that the yolk-stalk has usually been com- 

 pletely resorbed, and that only traces of the allantois can be seen, Y . The blood- 

 vessels have grown ; there are two arteries, .4 , A', and a single vein, V. Around 



Fig. 211. — Cross-section of a Human Umbilical 



Cord at Term. 

 A, ./', Umbilical arteries much contracted. V, Um- 

 bilical vein. }', Remnant of allantois. X' 2c " ain s. 



Ent 



Fig. 212. — Section of the Allantois from a 



Human Umbilical Cord of Three Months. 



enl, Allantoic entoderm, mes, Mesoderm. X 34° 



diams. 



.v.. *• 







P. 



\v 



. 



¥ s/ 



"■■■ -« . 



t 



K v../ , i 77/ . >t. 



% . 





^«,v< lis ,-®a**< r*imt , 



%?: 



:\ 







w ; 



r' f 



■ 



*N. 



rr*Ws 



Fin. 213. — Connective Tissue from thb Umbilical Cord of a Human Embryo of 21 mm. Stained 

 wiiii Alum Cochineal and Eosin. x 540 diams. 



11. Nucleus. /, Protoplasmic network. 



