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Ximna:a pereara* 



By William Nelson.* 



LIMN^A PEREGRA — or, as it has been variously named, 

 The wide-mouthed Helix, The Mud Snail, The Traveller, 

 The Wanderer, The Wandering Mud Snail, etc. — is pos- 

 sessed of a rather long history. The first notice of it that I have 

 seen is by Martin Lister, published in 1678. It has since then 

 been described by a great number of writers, and has become 

 possessed of a long string of names or synonyms, of which I have 

 collected upwards of two hundred. These are in addition to the 

 generic and sub-generic synonyms, and as the process is still 

 going on there is no fixing the limits of its titles. The chief 

 offenders in this respect are the French conchologists. The 

 Germans are bad enough, though not nearly so culpable as the 

 Bourguignat school. We ourselves are not without blame in this 

 particular, as with some of our recognised authorities the chief 

 requisite to command a new specific name seems only to be that 

 it shall be found in a part of the world which has not previously 

 been well explored ; for it is no doubt much easier to sit down 

 and describe under a new name than to laboriously overhaul what 

 has already been written, and refer the form to its proper place in 

 the genus to which it may belong. Another reason for the 

 enormous mass of synonyms which has gathered round this 

 species is, no doubt, the great variation in size, colour, shape, and 

 texture, which again is accounted for by its excessively wide dis- 

 tribution and the great differences in its environment. 



Passing over its ordinal and generic characters and coming to 

 the species, the animal may be described as having the tentacles 

 triangular, flat ; the foot broad, obtusely rounded, and broader in 

 front, and gradually narrowing, and somewhat pointed behind, and 

 the underside of the foot grey. 



The body varies greatly in colour and has been described by 

 different observers as being dark-grey, brown, greenish brown, 

 olive-yellow, or yellowish grey, often mottled with small ring-like 



*Read before the Leeds Branch of the Conchological Society, Oct. 10, 1895. 



