158 
W. Bernard Crow. 
Certainly then Volvo. v, Sphcerella and Steplianosphcera represent 
one distinct type which stands out among the Chlamydomonadales. 
There is scarcely more reason for separating this line of affinity as 
a distinct family than there is for separating other small groups of 
genera which have arisen from Chlamydomonas, and which can in 
some cases he traced amongst the species of this genus itself 
[see 7]. In chloroplast structure the Sphaerellaceae appear to be 
related to Chlamydomonas through the forms known as Cldoro- 
gonium. In cell-wall structure the link is afforded by species of 
Chlamydomonas itself. Fritsch and Takeda [8] have described a 
species, C. sphagnicola which possesses a cell-wall of two layers, a 
thicker gelatinous inner investment and a thinner firm outer skin. 
They think the same difference probably exists in C. glceocystiformis 
Dill, whilst in C. angulosa Dill the inner gelatinous coat sometimes 
appears. Finally in Carleria Fritschi Takeda there is often a very 
well developed inner gelatinous layer. Thus the phylogeny of the 
little group of organisms included under the name of Sphaerellaceae 
is by no means obscure. It is almost certain that a careful study 
of the order Chlamydomonadales would reveal other lines of 
evolution no less interesting. 
Summary. 
Gonium, Pandorina and Eudorina are colonial members of 
the true Chlamydomonadaceae. 
Reproductive colonies of Pandorina possessing one to four 
sterile cells have been observed. 
The genus Volvox has arisen independently of the other known 
colonial Chlamydomonadales ; its systematic position is with the 
Sphaerellaceae rather than with the Chlamydomonadaceae as at 
present constituted. 
In conclusion I wish to thank Prof. Fritsch for helpful 
criticism. 
LITERATURE REFERRED TO. 
1. Bessey. A Synopsis of Plant Phyla. Univ. Studies, Vol. VIII, No. 4, 
1901. Lincoln, Nebraska. 
2. Butschli, O. “ Protozoen ” in Bronn’s “ Tierreich.” 1883. 
3. Calkins, G. N. “The Protozoa.’ 1 Columbia Univ. Biol. Series, 1901. 
4. Cavers, F. “ The Inter-relationships of Flagellata and Primitive Algae.” 
New Phytologist Reprint. No. 7, 1913. 
5. Chatton, E. “ Pleodorina californica A Hanyul sur Mer.” Bull. Sci. France 
et Belg.. t. 43. 1911. 
ti. Delage, Y., and Herouard. E. “ Traite de Zool. Concrete.,” t. I. “La 
Cellule et les Protozoaires, 1896. 
7. Dill, O. “ Die Gattung Chlamydomonas und ihre niichsten Verwandten.” 
Jahrb. f. wiss. Bot,, XXVIII, 1895. 
