fone NN Aeris. 
VoL. Ix. AUGUST, 1895. No. 4 
PLEUROCERA SUBULARE IN WATER-MAINS. 
BY CHAS. T. SIMPSON. 
The U.S. National Museum has recently received from the Han- 
nibal Water Co., of Hannibal, Mo. (through Mr. Chas. T. Lewis), a 
number of dead shells of Plewrocera subulare Lea, taken from the 
mains and pipes of the company in that city. 
Mr. Lewis states that they accumulate at the cocks and faucets, 
and seriously retard the flow of the water, putting the company to 
considerable expense to remove them; also, that none have been 
found in their reservoirs or settling-wells, and they have never seen 
them in the Mississippi River. 
The specimens taken in the company’s pipes are always dead, and 
are only found in a space of perhaps 12 to 15 blocks, and not all 
the pipes in this area are infested. 
This species has been found as far west as the White River, Car- 
roll Co., Arkansas, and in the Mississippi River at Davenport, from 
which localities specimens were obtained that are now in the Na- 
tional Museum Collection, though the range of this form is mostly 
to the eastward of these localities. It is probable that the eggs or 
very young entered the mains through the strainers and took up 
their abode in certain favorable localities in the pipes, where food 
was brought to them by the currents, or existed in abundance, and 
that a more careful search would disclose them in a living state in 
the service pipes. 
