BY G. I. PLAYFAIR. 527 



the investing mucus. The connecting filament arises at the 

 angle. Tn the shape of the cells, this form i-ecalls VolvuHna 

 Steinii, which also has, sometimes, a series of c.v. i-ound the 

 circumference. 



VoLvox Carteri stein. (PI. Ivi., f.21, 22). 



Coenob. diam. ad 900; cell. diam. 4-5, inter se distant. 7-10; 

 zygo. immat. diam. 44-46, matur. ad 60/j-. 



Lismore (311, 327, 328). 



Cf. Carter, Ann. Mag. Nat. Hist., Ser. 2, Vol. iii. 1 have not 

 access, unfortunately, either to Carter's paper or to that of Stein 

 (the species is not mentioned in his Naturg. d. FlagelL); but 

 Lemmermann, Das Plankton schwedischer Gewasser, p. 105, in 

 one of his very useful little reviews of various genera, gives the 

 name, with the remark that the zygotes "are said to possess an 

 undulate membrane." By this character, I was able to recognise 

 the species. The ccenobium is like that of V. tertius Meyer, with 

 globular cells which, even under the yV obj., show no signs of 

 connecting filaments. It is the immature zygote which has an 

 undulate membrane (cell. diam. 31-33, lat. max. 44-46/>t); when 

 mature, the undulations have been produced into stout, slightly 

 curved spines (cell. diam. 36-37, lat. max. 53-60/x). Several dozen 

 zygotes in the ccenobium. I have the species from two places at 

 Lismore; it would appear to be the first time that this Volvox 

 has been recorded since Carter discovered it in India, fifty years, 

 or so, ago. 



Fam. PLEUROCOCCACE.E. 



Genus Elakatothrix Wille. 



Elakatothrix gelatinosa Wille. (PI. Ivii., f.l, 2). 



Cell. long. 15, lat. 3/x. Sj^dney Water-supply (100). 



Cf. Wille, Conj. u. Chloroph., p.38, fig.l8A-E ; W. k G. S. 



West, Phytoplankton Eng. Lake Distr. (Naturalist, 1909), p. 291, 



f.6. A ccenobium of four lately-divided cells (8 x 2/jt), and a 



single full-grown cell (15 x 3//.) noted in the filtrates of the Sydney 



Water-supply. This organism bears a suspicious resemblance to 



Spirotcenia acuta Hilse {see W. k G. S. West, Brit. Desm., i., PI, 



