216 Hazen: Lire History OF SPHAERELLA LACUSTRIS 
to the lime in the water. It seems more probable, however, that 
it is simply because the urns provide the conditions of light, aéra- 
tion, and evaporation demanded by .S?^aere//a. Further support of 
this view is found in the fact that Alexander Braun (’51) records the 
occurrence of this alga not only in basins of granite and sandstone, 
but also in holy water urns of iron and in a tin roof-gutter. 
Dr. H. M. Richards has obtained Sphaercl/a from dripping 
rocks above high tide at Nahant, Mass. I have found it in a 
similar place in New York under an overhanging cliff, where the 
supply of moisture frequently fails even in winter. 
This alga was distributed as Haematococcus lacustris (Girod) 
Rostaf. in the Phycotheca Boreali Americana (no. 114) The 
material was collected at Bridgeport, Conn., by Mr. Isaac Hol- 
. den, whoinforms me that it “formed a soft coating on the vertical 
face of rough-hewn stones of the abutment of the dam, where the 
water percolated through the crevices and trickled down the sur- 
face. It was very abundant for several seasons, but has not ap- 
peared lately. On sloping and horizontal rocks, which had become 
dry and exposed to the sun, I have seen it forming a closely 
adherent thin red film, which could not be removed without 
difficulty." I have scraped such a red coating from a sloping 
ledge at Richmond, Vermont, which was washed by a very small 
spring in summer. At certain times, after an increase in the vol- 
ume and force of the water, much less of the Sphaerella was to be 
seen. 
Some years ago the fountain in the college yard at Cambridge, 
Mass., was green with zooids of Sphaerella for a time in the spring, 
but Dr. Farlow informs me that last year none could be found. 
It will be noticed that in the last three localities conditions were 
unfavorable for the persistence of an organism which may be so 
easily swept away by an unusual force of water. We are, there- 
fore, justified in concluding that the small rock basins provide the 
most secure home for Sphaerella. 
THE RESTING CONDITION 
In the typical resting-cells of Sphaere//a which vary from eight to 
eighty microns in diameter, the only structure visible is the spherical 
mass of protoplasm closely enveloped in a thick membrane of cel- 
