PLATE 12 



EXPLANATION OF FIGURES 



Fig. 14 Photomicrograph of a sagittal section taken through the liead and 

 pharynx of a twenty-two-day rainbow trout embryo; showing the rehitions of 

 the subocuhir lymph sac (1) to the 63-6, the hyoidean arterj' (15) and the olfactory 

 pit (33); injected embryo. P. E. C. 816. 



Fig. 15 Photomicrograph of a transverse section taken through the subocular 

 Ij'mph sacs of a twenty-day steelhead trout embryo. The subocular sac (1) on 

 the right side of the figure is filled with blood, which has passed into the sac from 

 the veins through the lateral pharyngeal l,ymphatic. P. E. C. 636, slide 1, sec- 

 tion 67. 



REFERENCES 



1, Subocular h^mph sac 15, Hyoidean artery 



6, Precardinal or jugular vein 33, Olfactory pit 



98 



