222 Wisconsin Academy of Sciences, Arts, and Letters. 
servations made in 1910, one sounding showed a depth of 215 m. 
The slopes of the volcanic islands below the water seem to be 
very steep. A sounding about 200 m. south of the larger island 
showed a depth of 170 m. and a depth, of nearly 200 m. was 
found a short distance east of the islands. 
Like lake Atitlan, the larger aquatic plants are not very 
abundant in lake Ilopango owing to the steep slopes of the bot¬ 
tom near shore. Chara seemed to be the commonest form in the 
shoaler water. 
The water was just a little more transparent than that of 
Atitlan, the disc disappearing from view at a depth of 10.5 m. 
The fishes inhabiting lake Ilopango are chiefly small and not 
very abundant. 
LAKE COATEPEQUE. 
The Laguna de Coatepeque is situated in the province of Santa 
Ana, republic of Salvador, some distance northwest of the city of 
San Salvador. Its geographical position is 89° 34' 25" west lon¬ 
gitude and 13° 49' 33" north latitude. It lies about 8 km. south¬ 
west of the city of Coatepeque, which is one of the stations on 
the Santa Ana branch of the Salvador railroad. 
The accompanying sketch map (fig. 4, p. 223) shows that the 
lake is almost quadrangular in outline. The east-west axis of 
the lake has a length of about 6.5 km. and the north-south one, 
about 5.5 km. The basin appears to be of volcanic origin and 
possesses crater-like characters. The lake is surrounded by a 
narrow margin of valley which has a gentle slope, but beyond 
this the shores rise abruptly to a height of 200 m. or more above 
the surface of the water, forming a continuous, unbroken rim. 
A short distance west of the lake are two volcanoes, Santa Ana 
and San Marcelino. The former rises to a height of 1830 m. 
above sea level. The surface of the lake is about 760 m. above 
sea level. 
The marginal valley affords an excellent location for chalets, 
a number of which are situated along the southern and eastern 
shores. A small island is located at the southwestern corner of 
the lake. The lake possesses neither stream inlet nor outlet. 
At the time of this visit, February 25, 1910, the water seemed 
to be somewhat higher than usual, as it was undercutting banks 
which had previously been above the horizon of the waves. The 
