JOURNAL OF CONCHOLOGY. 221 



ADDITIONAL NOTE ON PLANORBIS DILATATUS 

 AND PLANORBIS GLABER AT BURNLEY. 



By J. BATES. - 



Mr. F. C. Long and myself for the first time took Planorbis 

 dilatatus in June, 1886, amongst some Valvata piscinalis, in the 

 Paper Works lodge, Burnley. This lodge has no connection 

 whatever with any cotton-blowing machinery, the nearest cotton- 

 blowing room being near half-a-mile distant, and in the canal 

 near this mill I could find no trace whatever of P. dilatatus. 

 On July 5th, 1887, Mr. Long found it in thousands in the canal 

 opposite Temple's factory, where the cotton refuse is blown into 

 the canal, they were found along the canal for over a mile in 

 the direction of Hapton,but were most plentiful opposite the 

 mill. The specimens are not so fine as those from the Paper 

 Mill lodge. Our first idea was that the warm water had some- 

 thing to do with the lodge specimens being so large, but the 

 canal specimens are very much smaller although the water is 

 very much warmer. In both localities they are found upon a 

 kind of Algae. 



Mr. Long also found P. glaber in June, 1886, at the Paper 

 Mill lodge, and has since also found one specimen in the 

 canal by the new bridge at Gannow, near Temple's factory. 



NOTES ON THE EPIDERMIS OR PERIOSTRACON 

 OF MOLLUSCA. 



By G. SHERRIFF TYE. 



(Read before the Conchological Society). 



All molluscous shells, at some period of their growth, have 

 an outer coat of animal matter which is formed and deposited by 

 the margin (collar) of the mantle, the shelly matter being de- 

 posited by the mantle itself, of which indeed it was once a part 

 as membrane or cellular structure, the cavities of which having 



