Fig. 3 Holdfast of bladder kelp, showing dichotomous branching of hapteres 

 and the disc-like si ruct ures formed on them where they come in contact with solid 

 objects. 



Fig. 4 Series of juvenile bladder kelps collected at Puget Sound Marine Sta- 

 tion, July, 1911. 



Fig. 5 A juvenile bladder kelp just beginning to form its pneumatocyst. 



Fig. 6 A young bladder kelp showing basal origin of the splitting of the lami- 

 nal region into numerous laminae. 



Fig. 7 Part of pneumatocyst of bladder kelp with a filamentous brown alga 

 epiphytic upon it. 



Fig. S Part of stipe of bladder kelp with A ntithamnion epithy tic upon it. Pho- 

 tographs by S. M. Zeller. 



S8 



