(90) 



DESCRIPTION OF PLATES. 

 Plate I. 



FIGS. 



1-4. Chlamydomonas marina, Cohn. x 1000. 

 5-13. Ankistrodesmus convolutus, Corda. x 1000. 



14-17. Oocystis elliptica, W. West, var. africana, G. S. West, var. n. x 1000. 

 Fig. 14 shows the lobed nature of the chloroplast ; fig. 15 the com- 

 pleted division of the protoplast into 8 young autospores ; fig. 16 a 

 colony of 4 cells, and fig. 17 a colony of 8 cells. In figs. 16 and 17 

 the disappearance of the mother-cell-wall is shown. 



18-29. Ecdysichlamys obliqua, G. S. West, gen. et sp. n. x 800. Figs. 18-20, 

 normal vegetative cells ; 19, cell stained with hematoxylin to show 

 the nucleus; 21-23, showing distention of outer layer of cell-wall; 

 24 and 25, showing the ecdysis of lamellae from the wall; 26-29, 

 autospore-formation. n, nucleus; py, pyrenoid. 



30-32. Pediastrum Pearsoni, G. S. West, sp. n. x 500. Fig. 31 is the side- 

 view of a colony to show the oblique disposition of the marginal 

 processes. 



33-34. Tetraedron trigonum, (Nag.) Hansg., var. isoscelum, G. S. West, var. n. 

 x 1000. 



35. Rhizoclonium hieroglyphicum, Kiitz., var. Single cell of filament, 

 x 500. 



36-37. Homceothrix africana, G. S. West, sp. n. x 500. 



38. Zygospore of Cosmarium subcostatum, Nordst., forma minor, W. & 



G. S. West. x 500. 



39. Cosmarium bireme, Nordst., var. crassum, W. it G. S. West, forma. 



x 500. 



40. Cosmarium Pappekuilense, G. S. West, sp. n. x 500. 



41. Cosmarium <il<itttm, Kirchn., var. cequatoriense, Nordst., forma, x 500. 



42. Cosmarium Pearsoni, G. S. West, sp. n. x 500. 



Plate II. 



43-44. Enteromorpha gracillima, G. S. West, sp. n. Fig. 43, branched filaments, 

 natural size ; 44, small portion of branch showing outlines of cells, 

 x 500. 



45-46. Enteromorpha gracillima, forma breviramosa, G. S. West. Fig. 45, 

 filament, natural size; 46, small portion of branch showing bases of 

 two ramuli and the outlines of the cells, x 500. 



47. Cosmarium geometricum, W. & G. S. West, var. adoxoides, G. S. West, 



var. n. x 1000. 



48. Cosmarium Iccve, Rabenh., var. distentum, G. S. West, var. n. x 500. 

 49-50. (Edogonium inversum, Wittr. A form, x 500. 



51-53. (Edogonium Pringsheimii, Cramer, forma, x 500. Fig. 51 is a male 



filament showing antheridial cells. 

 54-60. Myxobactron hirudiforme, G. S. West, sp. n. x 1000. Fig. 60 shows 



the transverse division of the cell. The cell-contents are pale 



seruginous and quite homogeneous. 



