254 



Heterokontce 



Fig. 119. Cklorobotrys regular-is (West)B'ohlin, 

 from Tremethick Moor, Cornwall ( x 450). 



of the daughter-cells are at first much flattened, but afterwards 

 become more convex. Zoogonidia have not been observed. 



Bohlin was distinctly in error in referring this Alga to the 

 Chloromonadales, as the plants are strictly algal in character. 



The ordinary vegetative 

 condition of the orga- 

 nisms belonging to the 

 Chloromonadales is a 

 ciliated or flagellated 

 one, whereas a motile 

 condition of Chlorobotrys 

 has never been observed. 

 Moreover, Chlorobotrys 

 is a very abundant Alga 

 and one which I have 

 had under observation 

 for many years ; and the 

 motile condition, far 

 from being the ordinary state of the plant, must be exceptionally rare. 

 The genus is undoubtedly nearest to Botrydiopsis Borzi, but 

 differs in the smaller size of the cells, which are associated to form 

 colonies, and the prominent mucous investment. Moreover, it is 

 only found in still water, whereas Botrydiopsis inhabits running 

 water. 



Chi. regularis (West) Bohlin [Chlorococcum regulare West 1 ] is widely dis- 

 tributed and often abundant in the Sphagnum-bogs of the British Islands. 

 I have also examined numerous specimens of it from Norway, Switzerland 

 and the United States. The cells are 12 19 p. in diameter and the families 

 (with the mucous investments) are 34 90 p. in diameter; fig. 119. 



Genus Ophiocytium Nag., 1849. [Indus. Sciadium A. Br., 

 1855.] The cells are free or attached and generally many times 

 longer than the diameter. They are commonly solitary, but 

 sometimes colonial, and they are usually curved or spirally con- 

 torted. The apex of the cell may be capitate or apiculate and 

 is sometimes attenuated into a long spine. Each cell contains 

 several nuclei and a number of large parietal chromatophores of a 

 somewhat cylindrical form. The presence of oil drops is a feature 

 of some species. The cell- wall consists of a homogeneous lid fitted 

 to the apex of a long tube composed of apposed layers of pectose 



1 West in Journ. Roy. Micr. Soc. 1892, p. 737, t. x, f. 55. 



