Plate 61 



Fig. 1. Tetraedron regulare var. bifurcatum Wille, x 500 



Figs. 2, 3. Tetraedron regulare var. granulata Prescott, x 500 



Figs. 4-7. Tetraedron regulare var. incus Teiling, x 500 (6 and 

 7, after Smith ) 



Figs. 8-10. Tetraedron regulare var. torsum ( Turner ) Brunntha- 

 ler: 8 and 9, x 500 (after Smith); 10, x 1000 



Figs. 11, 12. Tetraedron trigonum (Naeg. ) Hansgirg, x 500 



Fig. 13. Tetraedron regulare var. incus fa. major Prescott, x 



2500 



Figs. 14-16. Tetraedron trigonum var. gracile (Reinsch) DeToni, 

 xlOOO 



Figs. 17, 18. Tetraedron tumidulum ( Reinsch ) Hansgirg, x 1000 



Figs. 19, 20. Cerasterias staurastroides West & West: 19, x 2500; 20, 

 x4000 



Fig. 21. Scenedesmus ahundans (Kirch.) Chodat, x 500 (after 



Smith) 



Figs. 22, 23. Scenedesmus ahundans var. asymmetrica (Schroed.) 

 G. M. Smith, X 500 (after Smith) 



Figs. 24, 25. Tetraedron verrucosum G. M. Smith, x 500 (after 

 Smith) 



Figs. 26, 27. Scenedesmus ahundans var. hrevicauda G. M. Smith, 

 X 500 ( redrawn from Smith ) 



Figs. 28, 29. Tetraedron Victorieae var. major G. M. Smith, x 500 

 ( after Smith ) 



782] 



