Fig. 18 Photograph of the ventral aspect of the head of a twenty-day rain- 

 bow trout embryo on which an attempt was made to inject the lymphatics and 

 the veins by injecting into the subocular lymph sacs (1) ; Spalteholz preparation. 



PLATE 14 



EXPL.\N.\T10X OF FIGURE 



Fig. 19 Photomicrograph of a frontal section taken through the anlagen of 

 the subocular lymph sacs (1) in a fourteen-day steelhead trout embryo. P. E. 

 C. 697, slide 1, section 69; injected embryo. 



REFERENCES 



1, Subocular lymph sac 



6, Precardinal or jugular vein 



22, Carotid artery 

 28, Infundibulum 



102 



