254 Carter. — Studies on the Chloroplasts of Desmids. I . 
Figs. 9CH2. Eu. verrucosum, Ehrenb. Fig. 90, front view; Fig. 91, longitudinal section; 
Fig. 92, transverse section (upper chloroplast rather torn). 
Fig. 93. Eu. affine, Ralfs. Front view. 
Figs. 94-7. Eu. ampullaceum , Ralfs. Fig. 94, front view of an individual with imperfectly 
developed chloroplast, possibly after rapid cell-division; Fig. 95, typical front view; Fig. 96, 
transverse section of specimen with entirely parietal chloroplasts ; Fig. 97, transverse section of 
typical specimen. 
Figs. 98, 99. Eu. insigne , Hass. Fig. 98, front view; Fig. 99, transverse section. 
Figs. 100-5. Eu. crassum , (Breb.) Kiitz. Fig. 100, front view, lower semi-cell in optical 
section; Fig. 101, transverse section; Fig. 102, specimen having an entirely parietal chloroplast; 
Fig. 103, optical longitudinal section of specimen having a chloroplast which is practically parietal, 
but has two strands passing through the interior of the cell; Figs. 104 and 105, optical longitudinal 
sections showing the shortening of the central axis. 
PLATE XVIII. 
Figs. 106, 107. Xanthidium antilopaeum > (Breb.) Kiitz. x 510. Fig. 106, front view ; Fig. 107, 
side view. 
Figs. 108-12. X. subhastiferum , West, var. Murrayi , W. and G. S. West, x 510. Figs. 108 
and 109, front view; Fig. no, longitudinal section passing through pyrenoids in the lateral region 
of the cell (contents of lower semi-cell not shown) ; Fig. in, longitudinal section nearer the middle 
line; Fig. 112, transverse section. 
Figs. 113, 114. X. fasciculatum, Ehrenb. x 510. Fig. 113, front view; Fig. 114, end view. 
Figs. 115, 116. X. cristatum , Breb. x 510. Fig. 115, front view; Fig. 116, end view. 
Figs. 117, 118. X. aculeatum , Ehrenb. x 510. Fig. 117, front view; Fig. 118, optical 
transverse section. 
Figs. 119-26. X. Brebissonii , Ralfs. x 510. Figs. 119, 120, and 121, front view, side view 
and optical transverse section of a typical specimen; Figs. 122-6, optical transverse sections of 
various individuals, showing the variation in number and size of the pyrenoids, and transitions from 
the axile to the parietal disposition of the chloroplasts. 
Figs. 127, 128. X. acanthophorum , Nordst. x 810. Fig. 127, front view, lower semi-cell in 
optical section ; Fig. 128, side view. 
Figs. 129-32. X. armatum, (Br^b.) Rabenh. x 510. Fig. 129, front view of individual whose 
chloroplast is packed with stroma-starch; Fig. 130, front view of specimen containing little starch 
except that round the pyrenoids; Fig. 131, longitudinal section; Fig. 132, transverse section. 
