978 



XIV. ALGM. 



Pediaatrum Rotula 

 (mag.). 



Pediastrum granulatum. Split cell, 



emitting its zoospores enveloped in 



mucilage. (A. Brann.) 



P. granulatum. 



Zoospores, free or 



enveloped in mucilage. 



(A. Braun.) 



Closterium I/unula. 



At the moment of 



union (mag.). 



m 



Cocconema lanceolatum. 

 Toung individuals. 



Cocconema lanceolatum. Adult 



individual having produced a 



sporangium filled with zoospores. 



P?'Otococcus nivalis, 

 in various stages of growth (mag.). 



Mesocarpus 



parvuJtis. 



Filaments at the 



moment of 



union. . 



Gomphonema hpalinum. 

 Parasites on a filament of Conferva. 



Eunotia turgida. 

 Solitary individual. 



Eunotia turgida, 

 enveloped in mucilage. 

 Individuals having pro- 

 duced two sporangia 

 enclosing zoospores, 

 "which will each produce 

 a fresh individual. 



St7'iatella 



interrupla. 



One of the 



transversal 



frustules 



seen lengthwise, 



and showing 



its striEB. 



/ 



Striatella 



interrupta, 



with its lateral 



pedicel. 



Tribe VI. DIATOMUJE et BAOILLAUIEM, Ehrenberg, BreUsson, &c. 



Microscopic Algm (?) living in fresh, brackish, or salt water, generally prismatic 

 and rectangular, free sessile or pedicelled, naked or immersed in mucilage, and 



