BY G. I. PLAYFAli?. 519 



posito; niicleo in media cellula. Chloroplastide valida parietali, 

 inaculata (superficie externa scrobiculata); pyrenoide plerumque 

 nulla (in speciminibns notatis). 



Diam. 15-25; membr. 2-4; cell, matric. 40, aiitosp. 11-13//. 



Lismore (345, 350). 



Compare Chi. subcaudata Wille, Alg. Notizen ix.-xiv., p. 11 8, 

 T. iii., f. 12-1 8; W. & G. S. AVest, Frw. Alg. Brit. Antarct. Exp., 

 p.274, PI. xxiv., f.25-29. Generall}^ spherical without apical 

 projection; membrane thick, sometimes lamellar in two layers. 

 It is distinguished from Chi. glohulosa Perty, by the massive 

 parietal chloroplast evenly distributed round the cell-wall except, 

 of course, at the apex, and particularly by the fact that the outer 

 surface of the chloroplast is pitted, giving it a spotted appear- 

 ance all over. The central locellus is globular. Nucleus central; 

 stigma orange-coloured, a little above the middle ; pyrenoid 

 generally wanting. A mother-cell, however, was noted, contain- 

 ing four autospores, of which one had a distinct pyrenoid; in two 

 others, it was faintly indicated, and, in the fourth, it was entirely 

 absent. 



Var. OBLONGA, n.var. (PI Iv., f.l8), 

 Cellul* oblongi^; ceteris ut in forma typica. 

 Long 16, lat. 13|-/>t. Lismore (350). 



Var. PLANKTONICA, n.var. (PL Iv., f.l9). 



Celluhe oblongje, interdum apicem versus modice angustatse; 

 humili projectione apicali instructye, membrana tenuissima arete 

 adh^rente; stigmate nuUo nee pyrenoidi (in speciminibus notatis); 

 ceteris ut in forma typica. 



Long. 20-26, lat. 13-17/x. Lismore (347). 



This form has the same parietal chloroplast with scrobicula? 

 on the outer surface, but the membrane is very thin; there is a 

 slight apical protuberance, and, in specimens observed, the stigma 

 and pyrenoid were absent. 



Chlamydomonas metastigma Stein. (PI. Iv., f.20). 

 Forma stigmate luteo-fusco, bacillari, subapicali. 

 Long. 26, lat. 13/x. Lismore (327). 



