228 



Chloi'ophycece 



Genus Nephrocytium Nag., 1849. The cells are oblong, 

 ellipsoid or subcylindrical, slightly curved or sublunate, sometimes 

 almost reniform. There is at first a large expanded chloroplast in 

 each cell, furnished with a single pyrenoid, but later the chloroplast 

 fragments. The multiplication is by autospores similar to those 

 of Oocystis, and formed within the mother-cell soon after the 

 segmentation of the chloroplast. The young autospores are often 

 spirally disposed round the inside of the mother-cell-wall. The 

 genus is distinguished from Oocystis primarily by its curved cells 

 without any trace of apical thickenings. 



m 



Fig. 98. A, Nephrocytium obesum West, from Angle Tarn, Cumberland. B, N. 

 ecdysiscepanum West & G. S. West, from near Goring, Oxfordshire. C F, 

 N. hmatum West; C E, from near Bowness, Westmoreland; F, from near 

 Roundstone, Galway, Ireland. (All x 367.) 



N. Agardhianum Nag. (inclus. N. Ndgelii Grun.) is A widely distributed 

 species in the stagnant waters of small pools and lakes ; length of cells 12 

 22 JLI ; breadth 7 12 /*. N. obesum West is the largest species, characterized 

 by the short, stout cells and by the great thickness of the mother-cell-walls ; 

 length of cells 34 42 /* ; breadth 24 28 p. ; fig. 98 A. JV. lunatum West is u 

 characteristic species (supposed by Chodat to be a stage of ^V. Agardhianum) 

 which is very local, but sometimes abundant among submerged Sphagnum ; 

 length of cells 14 18 p. ; breadth 4 6'5 p. ; fig. 98 C F. JV. ecdysiscepanum 



