50 ALGAE IN PHYTOPLANKTON OF THE UNITED STATES 



Division Chlorophyta 

 Class Chlorophyceae 

 Order Chlorococcales 

 Family Oocystaceae 

 GENUS TETRAEDRON Kutzing, 1845 (fig. 19) 



MORPHOLOGY 



Solitary cells are polyhedral. Angles of the cells may be simple or pro- 

 duced into simple or furcate processes. Cell wall may be smooth or ver- 

 rucose. Cell may contain 1 to many parietal discoid to angular 

 chromatophores. 



REPRODUCTION 



The cell divides into 2, 4, 8, 16, or 32 autospores, which are im- 

 mediately released by rupture of the parent-cell wall. 



OCCURRENCE 



The genus is widely distributed, particularly in the euplankton and 

 tychoplankton. 



ENVIRONMENTAL CONDITIONS 



Standard 

 Range Mean deviation 



Temperature degrees Celsius 0.0 



pH 4.7 



Dissolved oxygen milligrams per liter .4 



Specific conductance micromho 10 



Total alkalinity milligrams per liter 



Total hardness do 6 



Total nitrogen do .03 



Total phospnorus do .0 



SPECIES INFORMATION 



Refer to Brunnthaler (1915), Reinsch (1888), Smith (1920, 1926), and 

 Prescott (1962). 



