GOMPHOSPHAERIA. 327 



Genus 112, COELOSPHAEBIUM, Naeg. 



Thallus spherical, vesicular, hollow ; containing many small 

 cells which are associated in families or scattered at the 

 periphery, immersed in a mucous stratum. 



Multiplication takes place by means of the peripheral cells, 

 which enlarge and escape through the external membrane and 

 develop daughter cells; also by the constriction and division of 

 maternal cells. 



COELOSPHAERIUM KUETZINGIANTJM, 



Families spherical, cells globose or subglobose, geminate, 

 or quaternate or scattered, loosely disposed ; cell contents 

 aeruginous, delicately granulose. 



Diameter of cells, 2-5 ^- ; families 60 JA more or less in 

 diameter. 



In ponds and pools ; stagnant waters. 

 Plate CCX, fig. 16. 



Genus 113, CLATHKOCYSTIS, Henfr. 



Thallus, a microscopic gelatinous body, primarily solid, then 

 saccate and later clathrate ; fragments of the broken thalli 

 occurring in irregularly lobed forms, composed of a colorless 

 matrix in which are imbedded large numbers of very small cells. 



Multiplication takes place by the division of the cells within 

 the thallus as it increases in size. 



CLATHROCYSTIS AERUOINOSA, Henfr. 



Cells aeruginous. Families singly, or a number united 

 forming a thallus which soon becomes largely perforated, 

 breaks and then dissolves. Often floating in large strata as 

 a glaucous green scum on fresh water pools. 



Diameter of cells, 2.5-3.5 /*; families, 30-130 //. 



Syn. Microhaloa aeruginosa, Kg. ; Microcystis Ichthyoblabe, Kg. ; 

 M. ichthyolabe, Breb. ; Polycystis aeruginom, Kg. 



Plate CCX, figs. 17, 18, two perforated thalli ; fig. 19, 

 when dissolved the cells float in mass. 



Genus 114, GOMPHOSPHAEE1 A, Kg. 



Cells wedge-shaped, peripheral 2-4-8 associated in radiating 



families, nestling in jelly, covered with a tegument and forming 

 a globose, free swimming thallus. Cells divide alternately in 

 three directions, 



