THE NAUTILUS. 



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 Pleurocera 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. 



