PLATE 1 



EXPLANATION OF FIGURES 



17 Reconstruction of the hepatic anlage of an Acanthias embryo 7.5 mm. 

 long (S.C. 14) showing longitudinal tubule ridges upon the wall of the lateral 

 hepatic pouch. 



18 Reconstruction of the hepatic anlage of an Acanthias embryo 10 mm. long 

 (S.C. 20) showing the formation of individual tubule anlagen from the tubule 

 ridges. 



19 Reconstruction of a hepatic tubule of an Acanthias embryo 13.3 mm. 

 long (S.C. 18) showing division into dorsal chamber and proximal neck and the 

 secondary tubules arising from the former. 



20 Reconstruction of a more highly developed tubule; from the same speci- 

 men as figure 19. 



21 Reconstruction of two simple tubules from the lateral hepatic pouch of an 

 Acanthias embryo 15 mm. long (H.E.C. 227). 



22 and 23 Two views of a reconstruction of a highly developed hepatic tubule 

 just prior to anastomosis; some of the secondary tubules are in contact: frojn the 

 same specimen as figure 21. 



24 Reconstruction of three anastomosing tubules ; from the same specimen as 

 figure 21; tubules A and B are completely fused; tubules C and A are in an early 

 stages of the process. 



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