PLATE 29 



EXPLANATION OF FIGURE 



Fig. 39 Photomicrograph of a transverse section of a twenty-two-day rain- 

 bow trout embryo, taken at the level of the third and fourth efferent aortic arches 

 (18 and 19 in figure 10); showing the relations of the precardinal lymphatics (5) 

 to the precardinal veins (6) in the posterior region of the pharynx. P. E. C. 648, 

 slide 2, section 51. 



REFERENCES 



3, The lateral pharyngeal lymphatic; 5, Precardinal or jugular lymphatics 



a continuous vessel through which 6, Precardinal or jugular vein 



the subocular lymph sac drains into 8', Caudal end of otocyst 



the veins in the trout 14, Dorsal aorta 



132 



