I 



•;\V >V * 



i 



Plate 9 



Portion of a basal layer cell of the epidermis of the tail of a frog tadpole 

 (Rana temporaria). Fixation: osmium tetroxide, stain : PTA. BM, basal 

 membrane; D, desmosomes; C, mesh-work of collagen fibrils which 

 support the basal membrane ; F, base of long process of dermal fibroblast, 

 which applies to and spreads over the surface of the collagen meshwork 

 presumably secreting further fibrils; M, mitochondrion; N, nucleus; 

 H, nuclear " pores "; v, small vesicles possibly arising from the pores; 

 and/, fibrils of cytoplasmic protein precursors of keratin. 



