EARLY GASTRULAE- 



INDUCED 

 TRUNK 



Fig. 41. The separation of the organizer into head and trunk organizers. The upper 

 figure illustrates a neural plate stage in which the anterior neural plate (left) has been 

 cut and the underlying roof of the archenteron has been exposed. This region of the 

 archenteron roof is then cut out and transferred to the blastocoel of an early gastrula. 

 The embryo (lower left) which develops from this gastrula possesses an induced head. 

 In the upper figure, the posterior neural plate (right) was cut out and the underlying 

 roof of the archenteron transplanted to the blastocoel of an early gastrula; an induced 

 secondary trunk projects from the side of the embryo (lower right). 



