Microscopic Studies of the Water of the 
Claremont-Laguna Region 
GENEVEIVE CORWIN 
The climatic conditions in Southern California where these studies were made, 
are unusual in that the rainy season occurs during the winter and early spring and 
there is practically no rainfall for the rest of the year. About 10 to 15 inches is the 
average yearly amount. With this small amount of precipitation, most of the 
streams dry up completely and the permanent pools diminish in size. This fact has 
a profound effect upon the life contained in the water. Just how this effect works 
out has not been determined. Some forms are able to dry up and still retain life, 
while others are killed by lack of moisture. Almost all the studies recorded in this 
paper were made on permanent pools and streams. 
Studies of the microscopic life of the Claremont-Laguna region were made in the 
early spring and summer, those of the Claremont region in February, March and 
April; and of the Laguna region during the last half of June and the month of 
July of the previous year. 
Considering the two places as a whole, in general there were more green algae 
than blue-green; more algae than Protozoa, the amoeboid Protozoa being fewest in 
number; the flagellate a little more numerous and the ciliate most frequent, both in 
species and individuals. The rotifers were rather rare, but were quite varied in 
form, from the simply constructed, active Colurus to the beautifully ciliated fixed 
Floscularia. The Gastrotricha were very rare. 
The chief difference between the Caremont and the Laguna regions is the abun- 
dance of aquatic life. This might be caused by the fact that most of the pools 
studied around the Laguna were close to the shore and the water may have been 
brackish. As a rule they were more stagnant than the Claremont water, with the 
exception of the Laguna Lakes. Perhaps the seasonal change may have had some- 
thing to do with this difference. The Claremont studies were made over a period 
of time twice as long as the other and much earlier in the season. However this 
may be, in almost every group there were more species in the Claremont region 
than the Laguna and in all other cases there were at least as many, with the 
one exception of the one desmid found in Claremont and not in Laguna. To 
summarize the comparison: ‘There were twice as many species of alge in the Clare- 
ment region as the Laguna; the same number of blue-green for both localitis but 
four times as many green in Clarement. The diatoms were quite numerous and 
varied in form in both places but there were only half as many species in Laguna. 
As mentioned before, one desmid was found in Clarement and none in Laguna. 
The Protozoa were quite abundant in both regions, there being three times as 
many in Claremont as in Laguna. In Claremont the amoeboid were twice as 
numerous as at Laguna. ‘There was a larger proportion of beautiful complicated 
forms in the Claremont region. There were three species of Stentor in Claremont 
and only two in Laguna. The restless little Euplotes, the graceful Spirostomium, the 
beautiful Stylonychia are illustrations of the variety of ciliates in Claremont. 
