CYCLOSTOMA ELEGANS. 323 



the perpendicular sides of the pit. Upon looking 

 further, a large number of specimens were found 

 dispersed in all directions. The shells were of every 

 gradation of growth from very young to full-sized. 

 They were scarcely at all altered, the outer surface 

 still retaining in part its usual colouring. They 

 were also for the most part extremely perfect, even 

 to the preservation of the opercle, which, in the case 

 of many individuals, still closed the aperture of the 

 shell. It is a matter of curious inquiry how these 

 shells came there, as the species is not known to 

 occur anywhere in the neighbourhood. Though I 

 have repeatedly searched for it in the living state, I 

 never met with it in the entire county of Cambridge- 

 shire, except in one locality near Linton,* and there 

 only obtained a single specimen. The shells at 

 Reche cannot have been brought from any distance, 

 nor can they have remained long in their present 

 unoccupied state. We can only suppose that they 

 must have existed at no very remote period, if they 

 do not still exist, somewhere in the immediate 

 vicinity of the above pits, into which they must have 

 been washed with the soil by the agency of some 

 land-flood. Possibly they were confined to a small 

 district, so that the entire race may have been 

 drowned. 



* Pennant, in his British Zoology, mentions its being found at 

 Madingley Wood, but I never observed it there myself. 



