BY G. 1. PLATFAIR. 



537 



Meyeii gives five fig\ii'es in illustration of his P. simplex, and 

 these have since been arranged as three difterent variations. 

 His fig.l is var. radiaiiH Lemni.(1897); figs. 2, 5 are f. orata (Ehr.) 

 llacib., {Asterodiction ovatu/ni Ehr., 1845); while figs. 3, \ arc 

 f. dathrata Schroter (1883). One of his figures, liowever, must 

 be left to represent the type, and it falls to fig.l to do this, var. 

 radians Lennn., being the last in order of priority. It seems to 

 have been overlooked also, that Meyen himself arranged it so 

 in the text. He says {I.e., p. 4) "c^ie unter Fiy.l mochte als die 

 Norm zu betrachten seyn.'' The 8-celled ccenobium without 

 central cells is, therefore, the type of P. simplex, and, incident- 

 ally also, of the genus Pediastrum. 



Forma clathrata (Schroter) Rac. (Text-fig.9). 

 Cienob. diam. 60-92; cell, periph. long. 26-28, lat. 12//. 

 Parramatta Park (99, 136). 



Ptdiastrum ximjilc 



Text-fig. 9. 

 f. cloJhrala (Schroter) Rue. 



( - ()()()). 



Schroter, in Jahresbericht d. Schles. Gles. fiir vaterland. 

 Cultur, 1883, p. 182; llaciborski, Gatunki rodz. Pediastrum, 1889, 

 p. 8. Syn., P. enoplou W. ifcG. S. West, Frw. Alg. Madag., 1895, 

 p. 81, T. 5, f.1,2; P. dathratum (Schrot.) Lemm., For.<ch. Biol. 



