ABBREVIATIONS 



b.l., basal layer of fetal ectoderm f-cap., fetal capillary 



end., endothelium m.h.s., maternal blood sinus 



ep., thicker, {ri-auular portion of (>pi- pi., e])ithelial plate 



thelium ^T/"-, fetal syncytium, trophoderm 



PLATE 1 



EXPLANATION OF FIGURES 



1 Portion of adult human renal glomerulus. Bowman's cajisule and walls 

 of convoluted tubules to the right of figure. Note the lobulation of the 

 glomerulus, the epithelial plates covering the capillaries at the border of the 

 capsular cavity, and the cell l)odies, as at "ep." on this border between the 

 plates. At "end." the plate and the underlying endothelium are each distinct. 

 X 640 diameters. 



2 and 3 Portions of immature mesonephric glomeruli from a human em- 

 bryo of about 10 mm. (Keibel, no. 149.5.) To show development of epithelial 

 plates and cell bodies. X circa 640 diameters. 



4 Portion of renal glomerulus of cat fetus of 8. .5 cm. Orientation as in 

 figure 1. Epithelial plates already present. X 640 diameters. 



6 Part of labyrinth of placenta of a ral)bit of 27 days, showing the endo- 

 thelium of the fetal capillaries and the succession of thin jilates and thicker 

 nucleated portions of the ectoderm, between capillary and maternal blood stream. 

 Copied from Duval's Atlas, Placenta des Rongeurs, figure 62. X 470 diameters. 



7 Portion of placenta of a guinea pig of the second month, similar to figure 

 6. Copied from Duval's Atlas, figure 262. X 300 diameters. 



206 



