CLASSES, ORDERS, ETC. 93 



(a) Shell light brown, attenuated, glossy, strongly striated in 

 line of growth ; whorls six to seven; suture well defined; mouth 

 pyriform, contracted above ; umbilicus minute. Height -/^ths 

 inch. Under stones and among decaying leaves. Moderately 

 common, but local. A. 



v, alba, white or colourless, transparent ; m. sinistrorsum, spire sinistral. 



