236 Hazen: Lire HISTORY OF SPHAERELLA LACUSTRIS 
with what Rostafinski knew in regard to C. pluvialis; (2) The 
fact (?)* that he was able to cultivate Chlamydococcus pluvialis in 
snow and to produce’zoospores at a low temperature. 
Now in making this physiological point, which remains un- 
confirmed, a ground of identity, more important points of differ- 
. ence of a similar nature have been left out of account. There is 
no record to show that Sphaerella nivalis may be cultivated at an 
ordinary temperature ; on the contrary, Chodat (’96) was unable to 
cultivate a red snow alga (which he supposed to be S. nivalis) ex- 
cept at a very low temperature. Furthermore, Cohn ( 54) was un- 
able to produce any development from “ red snow " material either 
when preserved in snow water or dried, while Braun (’51) records 
that motile cells were obtained from material of Sphaerella lucustris 
after it had been preserved seven years in a herbarium. 
I have myself attempted without success to cultivate in snow 
some of the “ red snow " cells which have preserved their color 
and normal appearance in spite of being kept in the melted snow 
for over two years. 
. The only important morphological difference seems to be that 
no protoplasmic threads connecting the central mass with the cell- 
wall have been observed in Sphaerella nivalis. This, together 
with the physiological difference: mentioned above, has seemed to 
Chodat (96) sufficient ground for maintaining even the generic 
distinctness of the two species, and he, therefore, retains the name 
Haematococcus lacustris to separate this species from Sphaerella ni- 
valis. It appears to me, however, that no more than a specific 
distinctness between the two forms can be maintained. 
NOMENCLATURE 
The nomenclature of Sphaerella is in such a confused state that 
it has given rise to some serious errors in regard to the life history. 
A brief historical sketch may therefore be found desirable. 
In 1828 Agardht established the genus Haematococcus and 
transferred to it the species he had previously called Protococcus 
uvalis.$. When Flotow published his memoir in 1844, not being 
* See section on vegetative division. 
TC. A. Agardh. Icon. Alg. Eur. Nos. 21-23, 1828. 
i Syst. Alg, I3. 1824. 
