208 



Tetrasporineas 



The genera are : Ch&topeltis Berthold, 1878 [inclus. Myxochaete Bohlin, 1894] ; 

 Ch&tosphseridium Klebahn, 1892 ; Dicoleon Klebahn, 1893 ; Conochaete Klebahn, 1893 ; 

 Diplochsete Collins, 1901 ; PolycliaRtophora W. & G. S. West, 1903 ; Oligocheetophora 

 G. S. -West, 1911. Nordstedtia Borzi (1892) is a doubtful genus. 



Some of the above genera have been regarded by various authors as reduced forms of 

 the Ulotrichales. Their habit as colonial unicells and their methods of multiplication do 

 not, however, lend much support to the view that they have originated from filamentous 



Fig. 136. A and B, Ch&tospli&ridium Priiigsheimii Klebahn. C, Ch. Pringsheimii var. 

 depressum G. S. West. D, a form of Conochsete comosa Klebahn. ch, chloroplast ; o, oil- 

 globule. E I, Oligochxtophora simplex Gr. S. West ; I, cell stained to show nucleus (n) 

 and starch-grains (s). A D, x 430 ; E I, x 330. 



forms. On the other hand, the sheathed bristle such as occurs in C/iSBtotp/ucridium, 

 Conochxte and Dicoleon is known elsewhere only in Coleocksete, the highest type of the 

 Ulotrichales ; and the curious unattached zoosporic forms of Coleocheete recently described 

 by Lambert ('10 B), in which the thallus is reduced to a few irregularly grouped cells, 

 might be said to throw light on the possible origin of the above-mentioned genera. There 

 is, however, no evidence to show that the sheathed bristle is of any phylogenetic importance, 

 and unsheathed bristles have certainly been developed independently in several groups of 



