828 AUSTRALIAN PRKSHWATER PLANKTON, 



gradually attenuate towards the apex, which is more or less 

 acuminate. Both this foi-m and the type are very active. 

 Distinct central nucleus, very rarely a pyrenoid, stigma wick- 

 shaped, orange or red, in the anterior third of the cell. It is 

 possible that this form is identical with Cld. mucicola Schm.,* 

 Alg. d. Schwarzw. u. d. Oberrli., p. 17, T. ii., f.4-S, which it very 

 much resembles. The latter, however, has a central pyrenoid, 

 and the n'}icle,ns jiosferior to it in the end of the cell ("In der 

 Korperinitte ist ein . . . pyrenoid und hinter demselben der sehr 

 kleine Zellkern") and no stigma. 



Genus Phacotus Perty. 

 Phacotus bullatus, n.sp. (PI. Ivi., f.21, 22). 



Celluhe, a fronte visa?, circulatje vel subcirculatif, margine 

 inajquali; a latere subhexagon^, infra apices constrictaj, apicibus 

 rotundatis, lateribus planis vel pauUulo retusis; a vertice cru- 

 ciatjie, late-lineares bullis magnis singulis utrinque in medio in- 

 structis; membrana aspera dilutissime rufescente. 



Cell. long. 13-14, lat. 13, crass. 9/x. 



Lismore (263). 



Found in quantity in company with Pteromonas cruciat.a, infra. 

 The cells, in front view, are generally subcircular; a broad ridge 

 runs down front and back, beginning and ending a little within 

 the apices. In lateral view, these show as produced ridges on 

 either side. End-view cruciform, the ridges appearing as large, 

 central, capitate bosses. Membrane very minutely rough, and 

 very faintly coloured. 



Var. coNicus, n.var. (PI. Ivi., f.23). 

 Cellulse conic*, fronte truncata?, a tergo acuminatse; lateribus 

 arcuatis. 



Cell. long. 16, lat. 13/i. 

 Lismore (263). 



* Ghl. mnsdcola Schiii., in Wille, Alg. Notizen ix.-xiv., p. 1.S6, by a slip 

 of the pen, for Sclimidle saj's, p. 18, "Sie lebt in der Gallerte des Frosch- 

 laiches" (frogspawn). 



