178 PATTEN. [VoL. II. 
EXPLANATION OF PLATE VII. 
Fic. 1. Surface view of the head of a young Acilius embryo. X 110. 
Fic. 2. The same. X I10. 
Fic. 3. The same. Dea ito): 
Fic. 3a. Side view of the same. : xXeamte: 
Fic. 4. Side view of the head. <auros 
Fic. 5. Ventral view of head. X 110. 
Fic. 5a. Side view of same head. x ie: 
Fic. 54. Dorsal view of dorsal edge of optic plate of same head. Xnles 
Fic. 6. Ventral view of head. X IIo. 
Fic. 6a. Side view of optic plate of the embryo in Fig. 6, showing arrangement of 
surface nuclei around the sense organ of each eye. X 190. 
Fic. 7. Ventral view of head just before rupture of embryonic membranes. 
Fic. 7a. Side view of same. X 110. 
