PLATE 3 



EXPLANATION OF FIGURES 



11 G-mni. Chclydra (second series). Sagittal section through second head 

 somite and outer portion of abducent muscle-mass. X 175. 



12 Section from same series somewhat further mediad, passing through the 

 two divisions of the abducent muscle-mass. X 175. 



13 9-mm. Chelydra. Sagittal section passing through outer wall of first 

 head somite, showing the M. obliquus inferior. X 135. 



14 10-mm. Chelydra. Sagittal section through middle of first head somite 

 and ganglion ciliare. X 135. 



170 



