4 6 



H ARC ITT. 



[Voi.. 1. 



and without indication of specific regenerative growth and ab- 

 solutely no hint at heteromorphism in the slightest way. 



Figs. 19 and 20 show experiments designed to further test 

 the regeneration of the manubrium. The operation of remov- 

 ing the organ was made on August 4. As will be seen in 

 the case of Fig. 19, about three-quarters of the animal were 

 excised, leaving one chymiferous canal fairly complete, and a 

 mere remnant of a second, the whole of the manubrium hav- 



a 



FIG. 18. 



ing been removed, as indicated by the line of the cut, a-b. 

 In Fig. 20 a wedge-shaped piece, about one-fourth the body 

 mass, including the manubrium, one entire canal and the 

 central portions of the other three, as indicated, was excised. 

 On August 5 the cut margins in each case had approxi- 

 mated each other and were evidently uniting. On August 7 

 the union was complete and the Medusae were swimming quite 

 freely and naturally. On August 9 the first indications of a 

 new manubrium were apparent, and in approximately the nor- 

 mal position. Its color and texture clearly indicated its forma- 



