Studies of Tissue Growth 



449 



give proportionately excessive "specific amounts of regeneration " 

 for these medusae most injured if one used the final diameters in 

 making calculations instead of the original diameters as measured 

 at the beginning of the experiment. 



Our examination shows the unsettled condition of opinion 

 regarding the relation between the degree of injury and the rate 



TABLE ni 



Regeneration of the oral-arms in Cassiopea, when one oral-arm is removed 



*Hole in center of disk due to parasite. 



•j-Not included in the average as no regeneration in 17 days. 



of regeneration. I determined, therefore, to perform more ex- 

 tensive experiments on several species of animals. A large num- 

 ber of Cassiopea xamachana and Ophiocoma riisei and Ophio- 

 coma echinata were selected for the purpose. 



It is advisable first to consider the species separately since they 



