PLATE 17 



EXPLANATION OF FIGURE 



Fig. 22 Photomicrograph of a transverse section taken through the subocular 

 lymph sacs (i) in a fourteen-day steelhead trout embryo. P. E. C. 695, slide 1, 

 section 70; injected embryo. 



REFERENCES 



1, Subocular lymph sac 22, Carotid artery 



6, Precardinal or jugular vein 28, Infundibulum 



20, Caudal end of eye 



108 



