BY G. I. PLAYFAIR. 



131 



Cell. vcg. 16 X 7, 17 X 8, 18 x 7, IS x .^ IS x 13, 2U x 10, 20 x 11, 

 22 X 11, 22 X 12//. 



Duck Creek, Clyde (74); Guildford (88); Botany Bay (91); 

 North Botany (92). 



Cf. W. AVest, Notes on Scotch Frw. Alg., in Journ. Bot., Apr., 

 1893, p. 99, P1.3;5;3, f.7, 8. 8yn., O. gkeocystiformis Borge, 

 Siissw. Clilor. von Feuerland u. Isla Desolacion, p. 2.3, T. ii., f.l. 

 This species is ublong-elliptic with obtusely rounded ends, or 

 narrowly elliptic with ends more acutely rounded, a minute and 

 very often indistinctly outlined 

 apiculus at each pole. In most of 

 the empty cells that I have ob- 

 served, there is a vagueness about 

 the outlines due to the membrane 

 being furnished with a relatively 

 broad, inner, mucous lining. It is 

 characteristic of all forms of this 

 species. West gives for dimen- 

 sions: long. cell. 11-15/x, lat. cell. 

 5-6 /A. Borge, for O. (jlwocystiformis, which seems to me to be 

 the same species, records long. cell. circ. 9//., crass. 4-5 "5//. Our 

 forms are larger, but I have noted the species once at 12 x 5/x, 



Var. SPLENDiDA, n.var. (PI. viii., f.2;)). 



Cellulse longe ovales, quam forma typica circa duplo majores. 

 Chloroplastides disciformes. 



Cell. long. .37, lat. 20-2 1/x. 



Lismore(240). 



In outline very like O. solitaria, for which I, at first, misto(jk 

 it. There is, however, no internal, apical incrassation, and the 

 cells are apiculate. It is about twice as large as the type, and 

 more elongated than \'ar. ubesa. The chloroplasts are disciform, 

 and arranged as in O. solitttria. 



Yar. ASVMMiCTKiCA (W. West) miiii. (Text-tig. 2 la). 

 Cell. veg. 12x5, 14x6 /a. 

 Botany (92), cum forma typica. 



Text-fig. 20. 



O. [iJiiorijMiformis Borge, ( x 7-40); 

 after Borge. 



