PLATE 25 



EXPLANATION OF FIGURE 



Fig. 33 Photomicrograph of a transverse section of a twenty-two-day rain- 

 bow trout embryo, taken at about the level of the hyoidean arteries; showing that 

 the continuous lateral pharyngeal l3'mphatic {3 in figures 10 and 33) occupies the 

 same relative position in the walls of the pharynx, as its independent anlagen 

 (3' in figures 31 and 32) of earlier stages. The medial pharyngeal lymphatic (4) 

 and independent anlagen (5') of the precardinal lymphatics are also shown in 

 figure 33. P. E. C. 6-lS, slide 2, section 10. 



REFERENCES 



3, The- lateral pharyngeal lymphatic; 

 a continuous vessel through which 

 the subocular lymph sac drains into 

 the veins in the trout 

 4, Medial pharyngeal lymphatic 

 5', Independent anlage of the pre- 

 cardinal lymphatic which lies con- 



tiguous to the precardinal vein and 

 just caudal to the medial pharyn- 

 geal communication (see fig. 10) 

 6, Precardinal or jugular vein 



15, Hyoidean artery- 



27, Root of dorsal aorta 



124 



