^ 4 



'1 



^ Mir-^wwr^j r- 



2 



MISS B. M. BRISTOL ON 



t ■ 



no taxonomic value amoiicj tlie lower aloa^, In siibmeririno; them all In tlie 

 genus Cldorochytrufm^ and finally In changing tlie name of the subfamily 



from Endospha.n"ace?c to Chlorochytriese. 



It was shown in addition*, in 1917, in the course of an extended invest!^ 



■ 



gation of a now species eventually named Chlorocliytrhnn grande^ that there 

 are a number of very good reasons for regarding Borzi's '' genus " Centro- 



sphwm also merely as a species of the wider genus Chlorocht/trium; so that 

 the genus, as it now^ stands, includes not only those species originally described 

 under the generic name Chlorocliyirium^ Gohn, but also those described under 

 the names Chlorocf/stis, Relnh., StomatocJi^trmm^ Cunningh., KiidosphAn^a^ 

 Klebs, Scotiaospluera^ Klebs, and Centrosphcra^ Borzi ; while the subfamily 

 Ohlorochytrie^e comprises but four genera — viz., Chlorocoecum^ Fries^ CJdoro- 

 chytrium^ Cohn, PhyUoUum^ Klebs, and Did^ococcus, Gerneck. 



Gardner t. In describing a new species of ChlorocJiytnum later in the year 

 1917, substantiated Prof. West's statements, at any rate in so far as the 

 *' genus ^^ Chlorocy&tis is concerned; while the following investigation of an 

 alga which can certainly be no other than that described by Klebs as ScotinO' 

 sphcera parado,ra^ shows beyond any question of doubt that Prof. "West's 

 statements hold also for the '' genus ^' Scotinosphajra^ Klebs. 



During the course of the present work, a study of the literature published 



on 



the 



genus Cldorochytnum, in its wider sense, has shown that there Is 



almost as much confusion amono^ the species as there was amonofthe ''genera" ; 



hence Prof. West suggested that this would be a good opportunii:y for a 



general review of the genus with a view to the simplification of the species. 



In all cases where possible a careful examination of the origlniil descrifitions 



and figures has been made, supplemented in the two species C, Lemmv and 



C. paradoxum by an investigation of the alga itselfy both in the living 



condition and by means of stained sections. The observations made on these 



two species, together with those made in connection with C. gravde J, have 



the past as 

 characteristic of a species or even of a genus can no longer be considered 



shown that certain features which have been regarded in 



as such, since they are found to vary considerably in different individuals of 

 the same species. For example^ the shapes of the cells and the nature and 

 extent of the thickenings of the cell- wall have been found to show very consi- 

 derable variation in both of the species C, paradoxum (Pis. 2 &3. figs. 17-30) 

 and <7. ^^an(f^, even though there was no external pressure of surrounding 

 host-tissue to affect the cells; Wright has also observed that in C. Cohnii 



those individuals developed in the Interior of the cell-tissue of the host are 



* Bristol, B. M, *' Ou the life-history and cytology of Cklorocjnjfnum yrande^ sp. noy." 

 Annals of Botany, vol. xxxL Jan, 1917. 



t Gardner, N. L, ^'New Pacific Coast Marine Algae, I-" Uniw California PubL in 

 Botany, vol. vi. no. 14, June 1917, 



X Bristol, loc, cit. 



