344 



RICHARD E. SCAMMON 



is 0.30 mm. The length of the fused anterior parts of the lateral 

 diverticula is 0.13 mm., while that of the still separated posterior 

 portions is approximately 0.17 mm. The posterior part of the 

 lateral liver anlagen, however, can hardly be called diverticula, 

 as they are little more than thickened plates of cells. The histo- 

 logic dififerences between the liver diverticula and the remainder 



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Rarcb. g. 



Hep.d. 



Fis- 7 Transverse section of an Acanthias embryo 0.4 mm. long (S.C. 19), 

 0.05 mm. posterior to the anterior wall of the yolk stalk. X 100. Hep.d., hepatic 

 diverticula; P-arch.g., para-archenteric groove. 



of the archenteron walls are shown in figure 7. The nuclei in the 

 walls of the lateral diverticula are no longer arranged in a single 

 layer, but are irregularly placed in the basal halves of the. cells. 

 Their elongation is noticeable. The cytoplasm of the cells of 

 the hepatic area is condensed and stains darkly as compared with 

 that of the cells above. The para-archenteric grooves are very 



