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ACHATIWA ACICULA (THE NEEDLE AGATE SHELL), 

 A-NB ITS OCCUERENCE AND DISTRIBUTION 

 OVER THE MAGNESIAN LIMESTONE OP 

 YORKSHIRE. 



By JOHN EMMET, F.L.S., 

 Bosto7i Spa; Secretary of the CoiLcJiological Section of the Yorkshire Naturalists Union. 



The late Dr. J. E. Gray, in his admirable edition of Dr. Turton's 

 Manual of British Shells, now superseded by Forbes and Hanley's 

 work, and more recently by that of Dr. Gwyn Jeffreys, gives the 

 following description of one of our loveliest British shells (the only 

 species we have of the genus), and it is sufficiently ample for all 

 practical purposes:— 



''Achaiina acicida. Needle agate shell. Shell slender, smooth, 

 polished, white, with six fiat volutions, lower one as long as all the 

 others ; mouth elliptical. Amongst the roots of trees, and at the 

 base of limestone rocks. Animal pellucid white, granulately 

 striated ; ten taenia retractile, cylindrical, upper pair longest, granular, 

 not thickened at the top, smooth, convexly truncated, v/ithout any 

 black spot (eyes) ; lower pair opposite the angles of the mouth ; foot 

 compressed, pointed behind ; breathing-hole large, rounded, in the 

 middle of the outer lip of the shell. Shell not a quarter of an inch 

 long, taper; aperture oval-oblong, appearing as if cut off at the 

 base, giving the end of the pillar the resemblance of a tooth ; outer 

 margin thin, not reflected, nor forming an umbilicus.' Probably 

 other conchologists have described much more simply. I will only 

 add that the name AcJiatiiia is supposed to be traceable to the Greek 

 and Latin root, achates = an agate, alluding to its polish. 



Having scrutinised the conchological lists of the Yorkshire 

 Naturalists' Union for the last two years, for the purpose of ascer- 

 taining if Achatina acicula had occurred anywhere, I find that there 

 is not a single record of its appearance during that period of time, 

 although Filey, York, Otley, Malham, Barnsley, Roche Abbey, 

 Sherburn, Hawes, Helmsley, Spurn, and Doncaster have been visited. 

 If it had been seen, such close observers as Taylor and Nelson, 

 ButtereU and Hey, and others, must have recognised and recorded it. 



Are we to infer that this enormous stretch of country is prolific in 

 other shells, and that the agate shell is conspicuous by its absence ? 

 I should have expected that it would have been taken at Sherburn, 

 Roche Abbey, Malham, and Doncaster; unfortunately, as I have 

 noticed, A. acicula has the knack of getting out of the way when the 

 conchologist is abroad. 



Naturalist, 



