Carter . — Studies on the Chloroplasts of Desmids . //. 303 
In most species a tendency was noticed for the axis of the chloroplast 
to become shortened in the apical lobe of the cell. This is more pronounced 
in the thicker celled species, in which the chloroplast may even tend to 
become parietal in this region by reason of the absence of the axis. Some- 
times the shortening of the axis in the median region extends through 
the whole length of the semi-cell, in which case two chloroplasts are present 
instead of one. 
(r» 
In conclusion, I wish to express my gratitude to the Birmingham 
Natural History and Philosophical Society and also to the Royal Society 
for grants to help in the cost of reproducing the plates illustrating this 
work. My thanks are also due to Professor G. S. West for much valuable 
help and advice throughout the investigation. 
The Botanical Laboratory, 
University of Birmingham. 
Bibliography. 
Delponte, J. B. (1873) : Specimen Desmidiacearum subalpinum , Augustae Taurinorum. Memor. 
d. R. Accad. d. Scienze di Torino, Ser. 2, vol. xxviii, 1873. 
Lutkemuller, J. (1910) : Zur Kenntnis der Desmidiaceen Bohmens. Verhandl. der k. k. zool.-bot, 
Gesell., lx, 1910. 
Ralfs, J. (1848) : The British Desmidiaceae. London, 1848. 
West, W. and G. S. (1904-11) : Monograph of the British Desmidiaceae. Ray Society, vol. i, 
1904; vol. ii, 1905; vol. iii,. 1 908 ; vol. iv, 1911. 
DESCRIPTION OF PLATES XIX AND XX. 
Illustrating Miss N. Carter’s paper on Chloroplasts of Desmids. II. 
During the prolonged processes of preparation the specific characters of Desmids often become 
obliterated, but all the species were identified, either in the living or carefully fixed condition, by 
Professor G. S. West. 
PLATE XIX. (All x 510). 
Fig. 1. Micrasterias conferta, Lund. 
Figs. 2-8. AI. denticulata , Breb. Fig. 2, front view ; Fig. 3, longitudinal median section ; 
Figs. 4-8, transverse sections taken at intervals from the sinus to the apex of the semi-cell, showing 
the large axile plate, and the comparatively small ridges cut in various directions. 
Figs. 9 and 10. M. rotata , (Grev.) Ralfs. Fig. 9, front view of semi-cell ; Fig. 10, slightly 
oblique transverse section, showing the median ridges cut transversely. 
Figs. 11 and 12. M. pinnatifida, (Kiitz.) Ralfs. Fig. 11, front view; Fig. 12, optical transverse 
section. 
PLATE XX. (All x 510). 
Figs. 13 and 14. M. Americana , (Ehrenb.) Ralfs, var. Lewisiana, West. Fig. 13, front view ; 
Fig. 14, optical transverse section, showing the axis of the chloroplast greatly distended with starch. 
