8 KANSAS UNIVERSITY SCIENCE BULLETIN. 



new factor. Yet on the third clay the exposed fronds were 

 discolored and soon became crisp, although somewhat leath- 

 ery. Some were placed back in the water to determine if they 

 would regain their former elasticity. Absence from camp 

 prevented observations for three days, but at the close of this 

 time the fronds had broken off to within eight inches of the 

 pneumatocyst and their ends showed the characteristic white, 

 decayed appearance to be found on all bald-heads. (Fig. 6.) 

 The check fronds seemed as healthy as ever and the dried ones 

 that had been returned to the water had broken off, save one, 

 and it broke when an attempt was made to lift it. It is to be 

 regretted that time did not permit a further test and that the 

 weather prevented field observations ; however, it is very sug- 

 gestive as to the causes of the bald-heads in Nos. 4, 15, 11, 

 19, etc. 



In the quieter waters, the upper portion of the stipe and the 

 pneumatocyst of many plants were found covered with a 

 dense growth of Ulva fasicata, this appearing on a greater 

 number of plants each week as the season progressed. So far 

 as could be determined it caused no injury to the plants, even 

 though they were sometimes fairly hidden by it. Enteromor- 

 pha was frequently found in the same situation. Antitham- 

 nion americcma and Porphyra nereocystis were common on the 

 deeper part of the stipe. Various Rhodophycete shared the 

 holdfasts with many specimens that were pulled up. Other 

 browns were often attached to the same stones as were the 

 Nereocysti. In the quieter waters the stipes and pneumato- 

 cysts were slimy with a heavy growth of diatoms. Many 

 fronds were spotted with the colonies of a Bryonzoan, Mem- 

 braniphora membrancete, in many cases almost hidden by its 

 white spots. (Fig. 7.) 



None of these, however, seem to cause the damage. So far 

 as observations have gone, the loss of the fronds is due to (1) 

 being eaten off and weakened by the snails; (2) to the drying 

 action of sun and wind when cast up over other plants by the 

 waves and currents and so exposed; and possibly (3) to fric- 

 tion against the rocky shores. It is recognized that these are 



