30. 

 The*? h~l h tot-1 length of 75 to SS go. and the hinl legs wore two-jointoi and 

 Ugited, and stood out (rorr. the body 00 *e to be vieible from the doreal aspect. 

 The raeults (Table 33, Figure 37) again oho* a oloee correaponlonoe u»t**en 

 the amount of oxygen and the rate of regenentic. Figure 38 le a curvw repre- 



senting the length of time necessary to regenerate 20$ of the amount raaovad 

 In the increasing concentrations of oxygen. As has been mentioned before, this 



-ve le similar to the curvee of Krogh (1914a) for Ihi iovelopiaent of frog 

 eggs at incr*-iain»; temperatures. 



The final exporiaent of the oxygen eerlee owes Its v»lu* to an 

 aeeident. The tadpolsa of this eerlee were 71 to 76 mm. long *nd h/j rudimen- 

 tary hin lege. Bo. 3 died without regeneration. Of the other five, Woe. 1 

 and 2, In 0.2 end !•! 0.0. O2 per liter respectively showed marked retardation 

 of regeneration when neaeured on tho twenty-first day (Table 33, Fig. 39), 

 During the twenty-ascend alght, the floe of water through the jars stopped, due 

 to |l«ggiBg of t -ing apparatus by sediment from the eater, an*! before this 



could be remedied the voter in the jars h&d beeosa w>sll asr&ted. During the 

 following night the cater again ceased to flow through the jure and again the 

 water in which tht* tmdyolma vera bce&sra aerate i. Since the tadpoles h»J been 



two days in aerated *3tar, ih* original purpose of tho experiment h-»J to 

 be abanlonai. An aerating jar with a rapid stream of air passing through it 

 wax placed Just after ixing bottle eo thst trie water entered tho first 



Jar aemtai. Measurements made on the twenty-sixth day of the experiment 

 ehoved that the tadpole in the first jar (0.2 c.c 0^ psr liter), which had 

 regenerated only 2.8j£ during the twenty-two days preceding the aeration of the 

 water, had regenerated 19.0£ in the four days following the change. The 

 tadpolsa already in hi ;her amounts of 2 , of course, showed less difference. 



I experiment is valuable as demonotr tin? th-st the decrease in regeneration 



