TEANSPLANTING NEURAL TUBE OF AMBLYSTOMA 



175 



A study of transverse sections was also made, but a description 

 of such sections would be merely a repetition of what has already 

 been described. For this reason but one transverse series will 

 be considered here, and that because it throws some light on the 

 completeness with which anatomical union is established through 

 the transplant. 



Embryo T. E. 7, shown in the figure with the control, had a 

 history similar to that of T. R. 4. Like the latter it showed 

 normal responses to stimuli twenty days after the operation, 

 was very active and, save for a slight bend in the posterior part 

 of its body and its slightly smaller size, behaved very much like 



Fig. 14 B, Embryo T.R.7, May 5. Operated April 8. A, control. 



the control. It was killed May 25th, twenty-five days after the 

 operation, and by that time its body had straightened out 

 considerably. 



Transverse sections showed complete fusion of the transplant, 

 but its location could be determined by the configuration of the 

 cells and the irregularity in the shape and position of the canal 

 as well as by the appearance of the regenerating notochord, which 

 in this case had been cut. (It was left intact in T. R. 4.) Figure 

 15, C, shows a transverse section passing just in front of the trans- 

 plant. D passes through the region of contact between the 

 transplant and the anterior stump. It is at once evident that 

 the cells are abnormally distributed and that there is no evidence 

 of a canal. E passes through the center of the transplant. It 

 shows a misplaced canal, and also the remains of the transplanted 



THE JOURNAL OF EXPERIMENTAL ZOOLOGY, VOL. 35, NO. 2 



