Quarterly Journal oj Conchology. 8i 



mis thin, yellowish ; spire rather small, exserted : whorls convex, 

 aperture rather wide ; columella thickened, suffused with brown, 

 outer lip somewhat thickened, scarcely reflexed. 



Hab. Catamarca (on the Andes of Peru). 



A fine species of the type represented by A. coliimellaris. 



[The original paper is accompanied by a coloured plate, to which the references 

 in this article apply. — Ed. Q.J.C] 



ON THE INTRODUCTION OF PLANORBIS DILATATUS 

 (Gould.) INTO THE BRITISH ISLES. 



Mr. Thos. Rogers read a paper before the Natural 

 History Section of the Manchester Literary and Philosophical 

 Society, on April 13th, 1870, upon the introduction of this 

 species, which he discovered in June, 1869, adhering to the 

 stones immediately below the surface of the water in the 

 Bolton cainal at Pendleton, and in close proximity to the 

 blowing room refuse discharge, and warm water discharge from 

 the engines of Messrs. Armitage's cotton mill. He also after- 

 wards found the same species under similar conditions in the 

 canal adjoining the mills of Messrs. Rylands, at Gorton. After 

 examining all the circumstances under which the MoUusk 

 was found, he was led to believe that its introduction into 

 this country was by means of American cotton, which had 

 been used for such like war purposes as barricades for steam- 

 boats or river defences by the soldiers in the civil war during 

 the presidency of Abraham Lincoln, and which had been acci- 

 dentally submerged in water and redried with the fry or spawn 

 masses of the Planorbis attached to its fibres previous to its 

 exportation to England, and this ultimately finding its way with 

 the cotton refuse into the canals adjoining the aforementioned 

 mills. He also remarked the abundance of the beautiful fresh 

 water Zoophyte, Plumatella repeiis, which is found in both hab- 

 itats of the Planorbis, and on the dead branches of which it 

 seems to find its favourite food. Mr. Rogers said that since 

 the year 1869 (when the moUusk was found in small • quantity) 

 it had increased its area of distribution and multiphed so much 

 as to be likely to become one of the commonest of our local 

 shells. — Extracted from the Proceedings of the Society. 



