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EDWARD MCCRADY, JR. 



wall have elongated, but have not yet obliterated the cavity 

 of the lens. These primitive lens fibers are still nucleate. 

 The pars optica of the retina shows only the cellular and 

 fibrous layers, no ganglionic or rod and cone layers having 



Esophagus 



Mesonephros 



Fig. 60 Dissection of abdominal viscera of embryo and early pouch young 

 (from Heuser, '21). A, stage 34. B, stage 35. 



yet differentiated. Pigmentation of the outer layer has just 

 begun. The cornea has not cleared. Mesenchyme which will 

 later give rise to the vitreous body is beginning to filter into 

 the optic cup, through which a single vascular loop runs. This 

 stage is similar to that of a 12.5-mm. human foetus except 



