GENERAL OBSERVATIONS 53 



corium. At this stage the corium has a perfectly plane 

 surface. 



The next stage will demonstrate the first step in the 



Fig. 26. — Section of Foot of Equine Foetus, Seventy-seven 



Days Old. 



The rete Malpighii rests on a plane corium ; the rent in the section is 

 along the line of the cells of the rete (Mettam). 



formation of the sensitive laminae.* The plain surface of 

 the corium has now become broken up, and what is noticed 



M 



*-- 



Fig. 27. — Section from Foot of Sheep Embryo. 

 It shows a pronounced epithelial ingrowth into the corium (Mettam). 



is that the broken-up appearance is due to the epithelial 

 cells irrupting and advancing en echelon into its connective 



* Sheep embryo, exact age unknown. 



