98 EMBEYOLOaY OF THE LOWEE VEETEBEATES oh. 



Meanwhile the wall of the vesicle lying next the outer skin 



-pin- 



ed. 



Fig. 55. — Sagittal sections through the pineal organ of embryos of Lacerta. 

 (After Novikoff, 1910.) 



A, /.. vivlpara, 3 mm. ; B, ditto, 4 mm. ; C, L. niuralis, 6 mm. ; D, L. vivipara, 9 mm. ect, external 

 ectoderm ; I, lens ; p.e, pineal eye ; p.n, pineal nerve ; p.s, pineal stalk ; pin, pineal outgrowth ; 

 thai, roof of thalamencephalon. 



