ALGOLOGICAL NOTES 



Fig. 6. — Pterontoiias Takedana, 

 X 1000. /, front view ; s, side 

 view ; e, end view. (From draw- 

 ing by Dr. H. Takeda.) 



Fig. 7. — Involution form of 

 Cloaterium Ehrenhergii with pa- 

 rietal chloroplasts, x 403. 

 monili fer urn, ' ^ Bot&n. Gazette, xli 



Long. cell, sine ala 15-5-16-9/a, 

 cum aLa 20-22 /x ; lat. cell, sine ala 

 12-13 /x, cum ala 17*5-22 /x; crass, 

 cell. 8-2-10 /x. (Fig. 6.) 



Hab. Earlswood Lakes, AYar- 

 wickshire (G. S. West) ; Ham Com- 

 mon, Sui-rey (W. B. Turrill). 



In the front view of the cell this 

 species is scarcely to be distinguished 

 from Pt. angulosa except by the larger 

 size of the pyrenoid. In the side and 

 end views, however, the body of the 

 protoplast is seen to occupy the whole 

 of the space within the external 

 membrane and is not deeply hollowed 

 as in Pt. angulosa (compare fig. 5 

 A-C, s and e with fig. 6, s. and e). 

 The anterior aperture in the external 

 membrane through which the cilia 

 pass is also narrower and less toothed 

 in the side view. 



The figures of this species and of 

 Pt. angulosa are all from drawings by 

 Dr. h! Takeda, and I take this oppor- 

 tunity to thank him for courteously 

 placing them at my disposal. 



XXIII. — An Abnormal Form of 

 Closterium Ehrenbergii. 



In the early part of May, 1913, 

 numerous examples of Closterium 

 Ehrenbergii were collected from small 

 ponds in the vicinity of Berkswell, 

 Warwickshire. These were placed, 

 along with certain filamentous Chlo- 

 rophyceae, in a small culture- jar. In 

 the course of a few weeks they had 

 multiplied very greatly by cell-divi- 

 sion, but as is so often the case in the 

 rapid multiplication of unicells under 

 unnatural conditions many monstrosi- 

 ties were produced. One of these, a 

 short, stunted form, with curiously 

 attenuated extremities, is worthy of 

 special mention, since it possessed 

 two parietal chloroplasts. In Closte- 

 rium Ehrenbergii, as in other species 

 of the genus, the chloroplasts are 

 axile. In CI. Ehrenbergii, Lutman='' 



* B. F. Lutman, "The Cell-Structure 

 of Closterium Ehrenbergii and Closterium 

 X, April, 1910. 



