PROTOPHYTES. 91 



their sporangia are smooth instead of tuberculated or 

 spiny. 



8. The families of Algae, called Oscillator iacece, Nosto- 

 chacece, Confervacece, and Conjugates, may all be consid- 

 ered as Protophytes, but a brief description only can be 

 given here. The structure is generally microscopic. 



The Oscillatoria are tubular filaments with partial 

 subdivisions, formed by the elongation of their primor- 

 dial cells, occurring in fresh and salt water, and on damp 

 ground. They have very curious movements, sometimes 

 swaying like a pendulum, and at others bending at the 

 extremity from one side to another, or moving straight 

 onward. 



Nostocs are beaded filaments lying in masses of green- 

 ish gelatinous matter. As the jelly forms rapidly in 

 damp weather, they have been termed " fallen stars." 

 The alchemists often refer to this substance, and it enters 

 into many of their recipes for the pretended transmuta- 

 tion of metals. 



The Conferva may be found in almost every pond or 

 ditch, but are especially abundant in running water. 

 They constitute the greater part of those green threads 

 which are found in streams, or near the sea-shore. Each 

 thread is a long cylinder, in which the endochrome, of a 

 green, brown, or purplish hue, is either distributed uni- 

 formly through the cell, or arranged in a net-work, or 

 spiral form. It increases by binary subdivision in the 

 terminal cell, as well as by zoospores produced within 

 the cells. 



The family Conjugates is so called because the fila- 

 ments are so constantly yoked together. They are 



