Hazen: Lire HISTORY oF SPHAERELLA LACUSTRIS 229 
A CONTRACTILE VACUOLE NOT PRESENT 
The presence of a contractile vacuole in this organism is al- 
leged by Cienkowski* and Bennett and Murray (’89). They are, 
however, undoubtedly in error on this point, for nothing of the 
kind has been recorded by the men who have become thoroughly 
acquainted with Sphaerella ; in fact, the existence of a contractile 
organ is expressly denied by Cohn ('54) 
There is also one of Bütschli's figures (PZ 43. f. ga) repre- 
senting a contractile vacuole in Haematococcus lacustris—a figure 
which has been copied by Hansgirg ('88) as Sphaerella lacustris, 
by Parker ('93) as Haematococcus lacustris,t} and by Lankester 
as Haematococcus palustris! in the article Protozoa in the Ency- 
clopaedia Brittanica. The figure which has caused all this con- 
fusion was copied by Bütschli from Stein’s figure (PZ. rs. f. 58) 
ot Chlamydococcus fluviatilis Stein, and was never intended 
to represent the species to which Bitschli applied it. It appears 
to me, indeed, that Stein's figure does not even represent a Ch/amy- 
dococcus (Sphaerella) for it has the red eye-spot, contractile 
vacuole, prominent nucleusf and single large pyrenoid which are 
characteristic of Ch/amydomonas, and in its development also, Stein's 
species is like this genus rather than like Sphaere/la ; it corresponds 
very closely to the Chlamydomonas rostrata described by Cien- 
kowski in the article above referred to, a form which I have col- 
lected several times near New York. 
THE COLORING MATTERS 
Cohn (’50) first described the pigment of the resting-cells as a 
scarlet red oil, soluble in alcohol and ether, and turned blue by iodin. 
Some years later Cohn (’67) gave to this pigment the name haemato- 
* L. Cienkowski. Ueber einige chlorophyllhaltige Gloeocapsen. Bot. Zeit. 23: 
25-27. 1865. 
T Parker was evidently unaware that AHaematococcus lacustris and H. pluvialis are 
synonyms, for he remarks that a contractile vacuole, though absent in Æ. pluvialis, is 
present in ZZ. /acustris, This confusion might h heen avoided had he noticed the 
footnote in which Biitschli accepts Cohn’s tiaia to the name ZZ. lacustris and re- 
adopts Æ. pluvialis. 
The nucleus is never distinguishable in living zooids of Spžaerelľa and it is even 
difficult to demonstrate it by simple staining processes. I have met with success by 
using osmic acid and carmine as suggested by McNab. Ann. and Mag. Nat. Hist. 12: 
124. 1883. 
