AQUATIC PLANTS IN POND CULTURE. 31 
exuberantly from bottom to surface and is removed by the use of a 
wire, about the size of a telegraph wire, loaded with weights and 
pulled through the pond much as a seine is hauled, except that it is 
jerked vigorously from side to side. In this way the tender growth 
of the Wyriophyllum is easily severed. It is then dragged ashore 
with a long rake similar to the one in use at San Marcos. The super- 
intendent prefers this method to the use of a scythe. 
Owing to the necessity for periodically removing the aquatic foli- 
age at pond-culture stations and the expense involved in the present 
methods of performing this task, it is obvious that here also is a field 
for experimentation. In this connection it seems proper to refer to 
the success of Mr. Charles T. Allen, who some years ago devised an 
aquatic mowing machine for the purpose of cutting eel grass on 
oyster grounds.?. Mr. Allen asserts that the machine will cut 2,400 
square feet of grass per minute in water 6 feet deep. Undoubtedly 
the machine is too large and heavy for use in small ponds, but it 
might perhaps be modified to suit the requirements of pond culture 
if the cutting knives can be successfully used on the vegetation of 
ponds. Gasoline or hand power could be substituted for steam power. 
“Report of the United States Commission of Fish and Fisheries for 1892, p. 477-478. 
O 
