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Figs. 107 and 108.— Sections through 1 1 a cyclopii trout embryo, the former through the middle of the median eyi 



and its lens, and the latter through the entranci ol the single optic nerve, This nerve is -een to divide at onci inl 

 branches for the two partly separate retinae. The fused condition ol the cerebral lobes will be noted, particularly in f ig 



01 details of structure see pp. 4042. Compare also with the two succeeding figures, and with PI. XXVI. fig. tit. ( 





Figs. 109 and 1 to. ["ran 1 1 ection ol [he head of a trout embryo showing the condition ol semi-cyclopia I 1 

 eyes, but they are close together, and the optii nervi is single, although there are two choroidal fissures, rhe internal 



recti are absent. A* in typical 1 yi lopia, the 1 ne between the bas 1 the brain and the trabeculae cranii, the 



tnterioi ends of which are separated by a wid< gap from th< rud mtary olfactory capsular 1 rhe latter are nol 



shown in this section. Compare with the two preced and with PI. XXVI. fig. in. See also p. 44. I -i.> 



PL. XXV. 



