DEVELOPMENT OF THE MAMMALIAN SPLEEN 295 



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B 



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Figs. A and B Sections of splenic siaa^es in the spleen of a 33-cm. jjig embryo. 

 A communication with the splenic pulp is retained through the delicate walls 

 that are composed of flattened reticular cells. 



Fig. C Part of a venous sinus and surrounding pulp in the spleen of an adult 

 pig. The sinus wall is composed of flattened reticular cells continuous with those 

 of the pulp. Numerous spaces between these cells and their processes provide 

 for free communication between the pulp and the sinus. 



THE AMERICAN JOLRNAL OF ANATOMY, VOL. 28, NO 



