1912] Ritter: The Marine Biological Station of San Diego 171 
the descending end of the siphon (d), also a channel in the con- 
erete, enters the lower aquarium. As the lower aquarium fills, 
the water after passing through a sereen fitting in the slots (s/.) 
ascends an outlet (e) similar to that in the upper aquarium. 
After reaching an overflow level about two inches below the 
top of the lower aquarium, the water flows downward through 
the descending stem of the siphon (/) into the floor gutter (gq). 
This gutter is 314 inches wide and, beginning in the most east- 
erly investigators’ room, runs in a straight line through the other 
five rooms, and conducts the water down a gentle slope through 
an exit at the west end of the building into the ocean. The 
eutter is installed only on the ground floor, the plan for the 
second story not being completed as yet. This scheme of cireu- 
lation very simply and effectively solves many difficulties. The 
water enters and leaves at the base of each aquarium; the pipes 
when clogged can be readily cleaned through their orifices (m). 
Overtlow is not likely to occur except in case of stoppage of 
outlets and absence of the investigator from the room. Even 
if, in an extreme case, water should overflow onto the floor, no 
damage would be done, for the cement floor is constructed lke 
the deck of a ship, so as to slope toward the gutter. With this 
system a constant level of water is maintained in the aquaria 
in such manner as to afford adequate circulation and simplicity 
in cleaning. 
The excellently lighted aquarium room is supplied with two 
floor tanks used as aquaria for large animals. Kach may be 
partitioned into two, in which case the water enters one com- 
partment by flowing over the partition from the other. The 
smaller tank is 5 feet 2 inches long, 3 feet 4 inches wide, and 5 
feet deep. The larger is 9 feet 3 inches long, 6 feet wide, and 
5 feet deep. The bottom in both is 16 inches below the floor 
and both are econerete, with walls 414 inches thick. In addition 
to these floor tanks the aquarium room is provided with four 
tables for serial aquaria. Each table is supphed with five or 
more rectangular aquaria 31 inches long and 21 inches wide, 
arranged in succession according to height, the highest being 
15 inches, the next adjacent being 2 inches lower, and so on. 
They are made of half-inch plate glass supported by galvanized 
