TYPES OF VERTEBRATE AND INVERTEBRATE EYES 13 



pr op.cr 



crneur 



sulc.op. 



sac vit 



Fig. 8. — Section passing through the Optic Groove and Optic Crest in the 

 Plane which is indicated by Arrows at S.i8 3 in the preceding Fig. 7. 



am. : Amnion. 



ar. ao. I. : arcus aortas I. 



area V. : area of fifth cranial nerve. 



atr. : atrium. 



bulb. ao. : bulbus aortas. 



cr. r.cur. : crista neuralis prosencephali. 



end. c. : endothelial canal of bulbus aortas. 



membr. br. I. : membrana branchialis I. 



pericard : pericardial cavity. 



ph. : pharyngeal cavity. 



pr. op. cr. : primordium opto-cristale. 



sac. vit. : vitelline sac. 



sulc. op. : sulcus opticus. 



