266 



176 (i75) 



FRESH-WATER BIOLOGY 



Elongate, spindle-shaped; chromatophores two, ribbon-shaped; 



eye-spot obscure Chlorangium Stein. 



Representative species. 



Chlorangium slentorinum Ehrenberg 1838. 



Flagella terminal, subequal. Attached during the sedentary stage by a 

 short, thick pedicel, singly or in groups up to ten or tvvelve zooids. Length 

 24 M- Pond water, often attached to various Entomostraca. 



Fig. 443. Chlorangium slentorinum. X 375- (After Stein.) 



Cuticle separated from body mass 178 



Cuticle smooth Haemotococcus Agardh. 



Cuticle rough Coccomonas Stein. 



Forming colonies 181 



Colonies plate-like with flagella upon one face only 182 



Colonies in a four-sided plate with envelop closely adherent. 

 Cells four or sixteen Gonium Miiller . . 183 



Four cells Gonium sociale Dujardin 1838. 



Sixteen cells Gonium pectomle MiiWer lyy^t- 



In this species each of the sixteen cells of the colony produces a 

 daughter colony of sixteen cells. As the daughter colonies develop, a 

 secondary shifting of the cells takes place resulting in individuals of 

 the adult colonies lying in one plane. 



Fig. 444. Gonium pedorale. X 350. (After Stein.) 



Colonies in a rounded plate with envelop swollen, oval, or spherical. 



Stephanosphaera Cohn. 

 Representative species. . . Stephanosphaera pluvialis Cohn 1853. 



Cells four or eight, ovoid or spindle-shaped, 

 with numerous processes. 



This form represents a transition from a 

 rosette arrangement of cells to a spherical 

 aggregate, the units being arranged in a 

 rosette but surrounded by a common gelati- 

 nous envelop. 



Fig. 445. Stephanosphaera pluvialis. /I .copula- 

 tion of gametes; ^, spore formation; C, cells with 

 protoplasmic processes; D, colony of eight cells. 

 A X 1325; B,C,DX 425. (After Hieronymus.) 



186 (181) Colonies spherical, ellipsoidal, or flattened, with flagella not confined 



to one face ^87 



187 (190) Colonies with cells crowded together 188 



