Fig. IS Diagrams showing the relation between, a) the axis of excentricity in 

 the superficial cleavage pattern of the micromeres of the early blastula and, 

 h) the median plane of the gastrula in forty-eight eggs of Cryptobranchus alle- 

 gheniensis. Each diagram represents the upper hemisphere of an egg; the small 

 round spot on the side toward the top of the page indicates a mark made with 

 Nile-blue sulphate on the side of the egg possessing the larger micromeres; the 

 arrow, pointing anteriorly, indicates the direction of the median plane of the 

 gastrula. 



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