370 



GRACE MEDES 



At this time, a possessed small tri-radiate spicules and later 

 formed skeletons which were normal in all but size, measuring 

 only 3.7, 41.56, 53.22, 62.37 and 64.24 on the various days. 

 The alkaline solutions showed at 24 hours a much greater excess 

 of size over the controls than did the corresponding culture of 

 Experiment 6, but the skeletons were irregular and in later stages 

 became far more abnormal. 



At this time the specimens in culture a were apparently in 

 a healthy condition, swimming about and their mouths and 

 alimentary tracts undergoing periodic contractions. This also 

 was true of those in solutions h and c, and slightly less marked 

 in d and e. In / the specimens were still swimming at the sur- 

 face, but were less active, and in g there was a much higher 

 death-rate and many of the specimens were swimming lower in 

 the dish. 



The third experiment in Series II was made with NaHCOa. 



Experiment 8. Plot 10. July 10, 1914 



a Sea-water 



b 224 cc. S. W. + 1 cc. 0.45M NaHCO, 



c 223 cc. S. W. + 2 cc. 0.45M NaHC03 



d 222 cc. S. W. + 3 cc. 0.45M NaHCOj 



e 221 cc. S. W. + 4 cc. 0.45M NaHCOs 



/ 220 cc. S. W. + 5 cc. 0.45M NaHCOs 



g 219 cc. S. W. + 6 CC. 0.45M NaHCOj 



The control growth-curve resembles that of Experiment 2 

 in that it reaches an early maximum which is followed by re- 

 sorption of the skeleton. Here, the period of greatest growth 

 occurs still earUer, before the 72 hour stage, after which a 



