SYNOPSIS OF THE ORDERS OF CHLOROSPERMEiE. 



1. SiPHONEJE. Rooting or basifixed. Frond simple or compound, formed either of a 



single, filiform, branching cell, or of many such cells united together in a spongy- 

 frond. (Marine or fresh-water.) 



2. DasycladEjE. Rooting. Fronds consisting of a simple or branched inarticulate 



axial thread, whorled with articulated ramelli. Spores spherical, developed in 

 proper fruit-cells. (Marine.) 



3. Valoniacej:. Rooting. Fronds polymorphous, formed of large vesicated cells, 



filled with watery endochrome. (Marine.) 



4. Ulvace^. Basifixed. Fronds tubular or flat, membranous, formed of minute 



quadrate cells. {Marine or in fresh water.) 



5. BATRACHOSPERMEiE. Basifixed. Fronds filiform ; the axis inarticulate, composed 



of minute cylindrical or polygonal cells, naked, or whorled with articulated ramelli. 

 Spores in moniliform strings, naked. {In fresh water.) 



6. Confervace.e. Basifixed or floating. Fronds filamentous, articulated. Endo- 



chrome diSused. Zoospores minute, formed in all the cells. (Marine or in fresh 

 water.) 



7. Zygnemace^. Floating. Fronds filamentous, articulated. Endochrome of some 



definite figure. Zoospores large, formed by the union of two endochromes (of 

 difierent cells), or by the bisection of a single endochrome. (In fresh water.) 



8. HydrodictyEjE. Floating. Frond forming a net-work with polygonal meshes ; 



each side of the mesh formed of a single cell. Viviparous. (In fresh water.) 



9. OsciLLATORiACEiE. Basifixed or free. Frond formed of subsimple filaments, having 



a membranous inarticulate tubular sheath, enclosing an annulated medulla, 

 composed of very short, lenticular, cellules. 



10. NosTOCHiNE-^E. Basifixed or free. Fronds consisting of moniliform jelly-coated 



threads, free or enclosed in a gelatinous matrix. 



11. Desmidiace^.* Microscopic, unicellular, green ; wall of the cell membranous : 



growth by semisection of the cell, and the evolutions of two new half-cells at 

 the medial line. 



12. Diatom ACEiE.* Microscopic, unicellular, yellow-brown ; wall of the cell silicious : 



growth and fructification as in the preceding Order. 



13. Palmellace^. Cells globose, or ellipsoidal, free, or lying in a gelatinous matrix, 



not forming either threads or membranes. Propagation by division of the 

 endochrome. 



* These Ordei-s are not included in the present work. The North American species have been ably worked 

 out by the late Professor J. W. Bailey of Westpoint, whose numerous memoirs on the siibject have a world- 

 wide reputation. The species are all of microscopic size, and some of them, from their extreme minuteness, 

 and the delicate sculpturing on their cell walls, form admirable test-objects for microscopes. 



