FCETAL NUTRITION: THE PLACENTA 461 



glands are, however, distended with secretion, and their 

 epithehum is normal. 



Next a change occurs such as Hubrecht described in the 

 hedgehog (see p. 449). The endothehum of some of the vessels 

 in the paraplacental layer prohferates irregularly round the 



VUaU 



Fig. 119.— The placenta of the bat. (From Nolf s " Etude des modifications 

 de la muqueuse uterine pendant la gestation chez le murin," Arch, de 

 Biol., vol. xiv., 1896.) 



m., muscularis ; a., unaltered mucosa; C.ep., epithelial layer; gl., glands; 

 C.pp., paraplacental layer with blood-spaces (6.) ; Art., artery running 

 towards trophoblast ; Ve., vein ; Tr., trophoblast with lacunae ; Vil. all., 

 allantoic viUi. 



lumen, and degenerates. In the bat, according to Nolf, the 

 vessels in which the change occurs are the venous capillaries, in 

 which the blood, returning from the placenta charged with 

 foetal excretory products, stagnates and produces the hyper- 

 plasia and simultaneous degeneration. Hubrecht, however. 



