Carter . — Studies on the Chloroplasts of Desmids . /. 253 
Fig. 19. N. interrupt urn, (Breb.) Liitkem. Individual having one pyrenoid and one chloroplast 
which is just beginning to constrict, probably a recently divided specimen, x 510. 
Fig. 20. Penittm spirostriolatum, Barker. Transverse section, x 510. 
PLATE XV. 
Fig. 21-5. Closterium 'ro stratum , Ehrenb. Fig. 21, specimen whose ridges undulate slightly, 
x 510; Fig. 22, another specimen with straight ridges, x 510 ; Fig. 23, longitudinal section, x 510 ; 
Fig. .24, transverse section, x 810; Fig. 25, transverse section near apical end of chloroplast, x 810. 
Figs. 26, 27. Cl. angustatum , Kiitz. Successive transverse sections, x 810. 
Figs. 28-30. Cl. regulare , Breb. Transverse sections of different individuals, x 810. 
Figs. 31-4. CL costatum , Corda. Fig. 3r x 510; Figs. 32-4, transverse sections of different 
individuals, x 810. 
Figs- 35-7* Cl. Dianae, Ehrenb. Fig. 33 x 510; Figs. 36 and 37, transverse sections, x 810. 
Figs. 38-43. Cl. striolatu?H y Ehrenb. Fig. 38 x 510 ; Fig. 39, part of a longitudinal tangential 
section showing anastomosis of the ridges, x 810 ; Fig. 40, transverse section showing the distending 
of the chloroplast with stroma-starch; Figs. 41-3, serial transverse sections of another individual 
containing little or no stroma-starch, and showing the varying combinations of the ridges, x 810. 
Fig. 44. Cl. Ehrenbergii, Menegh. Surface view showing proteid granules, x 810. 
Figs. 45, 46. Cl. -Siliqua, W. and G. S. West. Fig. 45 x 510; Fig. 46, transverse section, 
x 810. 
Figs. 47, 48. Cl. juncidum, Ralfs. Fig. 47 x 510; Fig. 48, transverse section, x 810. 
Fig. 49. Pleurotaeninm Trabecula , (Ehrenb.) Nag., var. rectum , (Delp.) W. and G. S. West 
x 510. 
PLATE XVI. 
(All x 510 with the exception of Figs. 77 and 81). 
Figs. 50-5. Euastrum bidentatum , Nag. Figs. 50 and 51, front view; Fig. 52, side view; 
Fig. 53, end view ; Fig. 54, an unusual specimen having two chloroplasts and two pyrenoids in each 
semi-cell ; Fig. 55, end view of same specimen. 
Figs. 56-8. Eu. dubium, Nag. Fig. 56, front view; Fig. 57, side view; Fig. 58, end view. 
Figs. 59-61. Eu. ansatum , Ralfs. Fig. 59, front view ; Fig. 60, side view; Fig. 61, transverse 
section. 
Fig. 62. Eu. sinuosum , Lenorm. Front view. 
Figs. 63-5. Eu. Didelta , (Turp.) Ralfs. Fig. 63, front view, lower semi-cell in optical section ; 
Fig. 64, longitudinal median section, showing the central axis of each semi-cell and the radiating 
plates cut irregularly ; Fig. 65, transverse section. 
Figs. 66-71. Eu. pectinatum , Breb. Fig. 66, front view ; Figs. 67 and 68, transverse sections ; 
Fig. 69, side view; Fig. 70, an unusual specimen ; Fig. 71, upper semi-cell of the same individual in 
optical transverse section. 
Figs. 72-5. Eu. oblongum , (Grev.) Ralfs. Fig. 72, front view, lower semi-cell in optical section ; 
Fig. 73, typical transverse section ; Figs. 74 and 75, transverse sections of unusual specimens. 
Figs. 76, 77. Tetmemorus granulatus , (Breb.) Ralfs. Fig. 76, slightly oblique front view ; 
Fig. 77, transverse section, x 810. 
Fig. 78. Tet. laevis, (Kiitz.) Ralfs. Front view. 
Figs. 79-81. Tet. Brtbissonii, (Menegh.) Ralfs. Fig. 79, oblique front view; Fig. 80, longi- 
tudinal median section, passing through the entire ridge on the right, and through the parietal 
expansion only on the left ; Fig. 81, transverse section, x 810. 
PLATE XVII. 
(All x 510.) 
Figs. 82, 83. Eu. ventricosunif Lund. Fig. 82, front view; Fig. 83, transverse section. 
Figs. 84-9. Eu. cuneatum , Jenner. Figs. 84 and 89, front view; Figs. 85 and 87, transverse 
sections ; Fig. 88, unusual specimen with part of one of its parietal plates free from the rest of the 
chloroplast; Fig. 86, optical transverse section of the same individual in the upper region of 
the semi-cell. 
