BY G. I. PLAYPAIR. 



125 



Ostenfeld and Wescnberg-Lund, Plankt. u£ two Icelandic 

 lakes, Prof. R. Soc. Edin., xxv., 1906, p.lll3, PI. i., f.8. Syn., 

 O. ^acMs^ris Ostenfeld, /.f., p. 235 (sec. auvfor. ipsnm). Ostenfeld 

 remarks: "The species .... has one pyrenoid in each chloroplast; 

 the chloroplasts are two or four in each cell, often tetrahedrally 

 arranged; the cells are four (rarely two) in a globular mucilage; 

 their shape is ellipsoid or ovate with subacute apices; length 22- 

 2(5 /*, breadth lG-20/tt." I noted, in river-gatherings, mother-cells 

 of this form in company with others of 0. Novce Semliiti var. ans- 

 tralica mihi. It is probably intermediate between the latter 

 and O. crassa. Var. Ostenfeldii differs from the type in being 

 more regularly elliptical, not so rhomboid, with sides regularly 

 arched, not bent in the middle, the apices not incrassate. It has 

 fewer chlox'oplasts also. 



OocYSTis LACUSTRis Chodat. (PL vii., f.20). 



"Cellulis binis vel quaternis in familiis consociatis, membrana 

 gelatinosa crassa, utroque fine cellulie leviter incrassata, late f usi- 

 formibus utroque acutis, chlo- 

 rophoro laminam formante sa^pe 

 dimidiato, pyrenoide munito vel 

 carente. Contentus ssepe oleo- 

 sus." Chodat, I.e. 



Cell, matric. 24 x 22, 30 x 22, 

 autosp. 9x.5, 14x9, 18x8, 

 18X9/X. 



Dunedin, N.Z., Northern 

 Reservoir. 



Chodat, Etudes de biologie 

 lacustre. Bull, de I'herb. Boissier, 1897, p.296, Pl.lO, f.1-7, 13; 

 Alg. vertes, p. 190, f.l05. The authoi-, by a strange oversight, 

 has given no dimensions in either publication. W. & G. S. West, 

 Plankton of some Irish Lakes, p. 107, record long, colon. 43-60, 

 long. cell. 14-22, lat. cell. 8-15; and G. 8. West, Third Tangan- 

 yika Exp., p. 141, long, colon. 39-54, long. cell. 12-20, lat. cell. 

 7-13//.; both agree very well with Australian specimens, except 

 that the colonies are larger. The type has either a single, 



Text-fig. 14. 

 (a) 0. lacvxtris Chod. ; after Chodat. 

 {h) OocyMella natanx Lemni.,( x 7oO); 

 after Lenniiermanii. 



