328 THE JOURNAL OF BOTANY 



The affinities of this organism are quite clear. It belongs to 

 the subfamily Chlamydomonadeae of the Volvocaceae. It differs 

 from Ghlamydomonas (including Ghloromonas ") in the compression 

 of its cells, in the relatively great length of its cilia, and in the 

 nature of its movements. 



Another somewhat similar genus of the Chlamydomonadese 

 with much compressed cells has recently been described by 

 Pascher f under the name of Scherffelia. This genus, like 

 Carteria, is furnished with four cilia, but differs from it in its 

 compressed cells, and in the possession of two chloroplasts (some- 

 times slightly joined at the base). In it Pascher includes two 

 freshwater species, S. duhia (Scherffel) Pascher and S. phacus 

 Pascher. The genus Scourfieldia bears exactly the same relation- 

 ship to CMamydomonas that Scherffelia does to Carteria. 



Scourfieldia coynplanata is much less than either of the 

 described species of Scherffelia. Apart from the possession of 

 only two ciha, the posterior extremity of the cell is much more 

 rounded, the single chloroplast is of a totally different character, 

 and the cilia are of much greater length. 



The transverse section of the cell of Scourfieldia complanata is 

 not unlike that of Scherffelia duhia, but differs considerably from 

 that of Scherffelia phacus. A diagrammatic representation of 

 such a section is given in fig. 3, F. 



XIII. — New and Interesting British Freshwater Alg^. 



1. Coleoch^te Nitellarum Jost in Ber. Deutsch. Bot. Ges. 

 xiii. 1895, p. 433. This Alga occurred abundantly on Nitella 

 flexuosa in a small pond at Sutton Coldfield, Warwickshire, in 

 June, 1909. The thinness of the cell-walls has been pointed out 

 by J. F. Lewis,! who has also given some details of the sexual 

 organs and fertilization. The first and, I believe, so far the only 

 British record, is by G. Lunam,§ who found the species in the 

 neighbourhood of Glasgow. 



2. Ch^tonema irregulare Nowak. Diam. cell. 5-8 /x. 

 Hab. Doncaster, W. Yorkshire. This rare member of the Chseto- 

 phoraceae has not previously been observed in the British Islands. 

 It was growing at the periphery of gelatinous colonies of the 

 Palmella-state of a species of Ghlamydomonas. 



* N. Wille in Nyt Magazin for Naturvidenskaherne, xli. 1903 (Algol. Notizen 

 IX.), regarded the genus Chloromonas Gobi as distinct from Ghlamydomonas 

 Ehrenb., although only differing in the absence of a pyrenoid from the chloro- 

 plast. In his revision of the Chlorophycege in Engler & Prantl's Pflanzen- 

 familien (1909), however, he no longer regards this separation as justifiable. 

 With this later view I am in complete agreement, as I have repeatedly stated 

 that in the Chlorophyceae the presence or absence of pyrenoids cannot be con- 

 sidered under any circumstances as of generic importance. 



t A. Pascher, " Zur Kenntnis zweier Volvokalen," Hediuigia, lii. 1912. In 

 this paper Pascher proposes the new group of the Carteriacete to include those 

 members of the Volvocacese in which each cell is furnished with four cilia. 



I J. F. Lewis in Johns Hopkins Univ. Calender, Notes Biol. Lab. March, 

 1907. 



§ G. Lunam in Glasgoiv Nxituralist, iii. 1910, p. 26. 



