226 Chlorophycece 



are irregularly disposed, and in the large enveloping mass of 







B 



Fig. 96. Kirchneriella obcsa (West) Schmidle. A, B, D and E, from Bowness, 

 Westmoreland ; C, from the plankton of Loch Mor Bharabhais, Lewis, Outer 

 Hebrides ( x 485). 



K. obesa (West) Schmidle (breadth of cells 2 9'5 p. ; apices 1-5 4 /* apart; 

 greatest diameter of cell 6 16 p.; fig. 96 A E) and K. lunaris (Kirchn.) 

 Mob. are widely distributed in the British Islands, occurring sparingly in the 

 small ponds and lakes, but in quantity in the plankton of the larger lakes. 



Sub-family IV. OOCYSTJDE.E. 



This sub-family is characterized by the globose or ellipsoid cells 

 (curved or even sublunate in Nephrocytivm), which are frequently 

 retained within the swollen wall of the old mother-cell. There 

 may be one or many chloroplasts in each cell, which are parietal 

 and usually contain one pyrenoid. In all except Palmellococcus 

 the cell-walls are firm and somewhat thick. The multiplication is 

 by autospores, which generally grow and attain their full size 

 whilst still forming part of the mother-colony. 



The following are the British genera : 



* Cells ellipsoid Oocystis. 



** Cells curved, subcylindrical or sublunate Nephrocytlnm. 



*** Cells spherical. 



t Cells large, solitary and free-floating Eremosplmra. 



tt Cells minute, forming a thin stratum Palmellococcus. 



t tt Cells minute, sparsely scattered and symbiotic Chlorella. 



