214 Wisconsin Academy of Sciences, Arts, and Letters. 
LIMNOLOGICAL STUDIES ON SOME LAKES IN 
CENTRAL AMERICA. 
BY C. JUDAY. 
During the month of February, 1910, four lakes situated in 
Central America were visited for the purpose of making some 
limnological observations on them. The purpose of these in¬ 
vestigations was to make such studies on these tropical lakes as 
had been made on a considerable number of lakes in the tem¬ 
perate zone so that comparisons could be made with respect to 
dissolved gases and net plankton content. It was the purpose, 
also, to obtain data concerning the vertical circulation of the 
waters of deep lakes possessing such markedly tropical charac¬ 
teristics. A permanent stratification, resulting in a permanent 
stagnation of the lower strata of water, doubtless, would have 
presented some interesting biological problems, but such condi¬ 
tions do not obtain in any of these lakes. Lastly, since they are 
situated in volcanic regions information was desired with re¬ 
spect to the effect of such phenomena on the dissolved gases as 
well as on the other substances held in solution by their waters. 
These four lakes lie on the Pacific slope of Central America. 
Two of them are situated in the republic of Guatemala and are 
known as lakes Amatitlan and Atitlan. The other two, lakes 
Ilopango and Coatepeque, are situated in the republic of Sal¬ 
vador. 
Cljmate. 
These four lakes lie far within the tropics, being located near 
the middle of the north tropical zone. Lake Atitlan is the most 
northerly and it is less than 15° from the equator. The general 
region in which they are situated has two seasons during the year, 
