374 E - A - ANDREWS. 



to the plankton, or swimming fauna, as well as to the microscopic 

 life attached to the summer vegetation of these waters. 



Its advent and departure in Chase's Creek, a branch of the 

 Severn, showed in 1914 even more suddenness than in 1913, while 

 its time of abundance was noticeably less though actual numbers 

 present were even more vast. 



Though searched for from the middle of June, every few days, 

 Folliculina was found first on July 19, 1914. It then appeared 

 only here and there, not on every plant of Elodea and on very few 

 plants of Potamogeton. On the sprays of Elodea the Folliculina 

 showed on comparatively few leaves, like black soot stuck on 

 the leaves; both isolated individuals and aggregates occurred 



i 



It 

 *# 





FIG. i. Leaf of Potamogeton showing scattered colonies of Folliculina. X3 

 diam. Photograph of preserved specimen. 



but there were very few large aggregates covering half the surface 

 of a single leaf. Most leaves had none, some leaves had many 

 scattered individuals. On the stems there were noticeable 

 numbers of the small form of sac. The occurrence on leaves 

 seemed entirely arbitrary as if from settlements of swimmers: the 

 Folliculina was not now crowded toward the tips of the sprays 

 but scattered along many inches of the spray. 



At the date of this first appearance, jellyfish had been common 

 for two weeks but the other conspicuous summer visitor to these 

 waters, the young menhaden now for the first time came along 

 the shores over the Elodea, which may be correlated with the 



