Carter . — Studies on the Chlorop lasts of Desmids. /. 217 
thorough work that has ever been done on the chloroplasts of Desmids, 
with the single exception of the more recent work of Lutman (1910, 1911) on 
Closterium. Liitkemuller was one of the few investigators who attempted 
to discover the real nature of the more complicated chloroplasts of the 
group. He worked for a considerable time on Desmids, and made many 
excellent preparations of the chloroplasts, but his untimely death in 1912 
prevented this work from being published. 
In their Monograph of the British Desmidiaceae, W. and G. S. West 
(1904-11) indicated the nature of the chloroplasts and the position of the 
pyrenoids in many members of the order, as far as this could be ascertained 
by superficial observation, noting in particular the variability of the chloro- 
plast in Cosmarium Subcucumis , Schmidle, and other species. The same 
authors (1896, 1897, 1902, 1903, 1907) and G. S. West (1914) have figured 
the chloroplasts in Roy a, W. and G. S. West, and also in some new species 
of Cylindrocystis , C. Americana^ W. and G. S. West , 1 C. ohesa, W. and G. S. 
West, and C. pyramidata , W. and G. S. West , 1 besides indicating the nature 
of the chloroplasts in several other species. 
Seeing that there is no exact information concerning the nature of the 
chromatophores in the great majority of Desmids, it was suggested by 
Professor G. S. West that the investigation of the chloroplasts of this group 
would be a useful and interesting study. 
Methods. 
With most Desmids, careful staining is essential for the investigation of 
the chloroplasts ; only in a very few species of Staurastrum , Cosmarium , 
and Closterium can the nature of the cell-contents be successfully determined 
in the living condition, and even in these staining is desirable in order to 
ascertain the number and position of the pyrenoids. In all others the con- 
tents are uniformly green in the living condition, or merely show a few 
darker bands, their real nature being quite obscure. With some of the 
thicker species, even in stained specimens it is quite impossible to make out 
with any certainty the structure of the chloroplasts, because of the extremely 
dense nature of the cell-contents, and sections are essential, as for example 
in the larger species of EiLastrum and Cosmarium . In the investigation of 
the chloroplasts of the large species of Euastrum particularly, sections 
revealed the most unexpected structure, and it is quite probable that their 
complicated construction would never have been understood by mere super- 
ficial observation. The same is most certainly true in the case of many 
other large Desmids, and with these also sectioning is the only means of 
obtaining accurate information. 
In the case of Cosmarium hire turn , Brdb., the cell- wall appeared to 
have a peculiar affinity for the stain used, iron-haematoxylin staining quite 
1 It is most probable that these two species really belong to the genus Cosmarium. 
