258 TAYLOR: VARIATION OF LIMN^.A PEREGRA. 



There has been much speculation and conjecture upon the 

 probable causes of sinistrorsity, reflection of the outer lip, 

 malleation of the whorls, and other divergences from the normal 

 shell, but these variations have not yet received sufficient atten- 

 tion to enable us to accept with any confidence the various 

 theories that have been propounded to account for them. 



The two best known forms, L. peregrn and L. ovata, are 

 recognised by European conchologistsgenerally as distinct species 

 but in this country are considered to be mere modifications of the 

 same specific type, and Herr Julius Hazay, a leading continental 

 conchologist, has lately accepted the same view, and states that 

 he has verified by actual experiment that these two so-called 

 species are merely biological varieties, which may be produced 

 at will by simply placing the ova under suitable conditions — 

 thus typical L. peregra is produced from ova of L. ovata if 

 placed in " hard " running water, and that L. ovata may be 

 developed from the ova oi L. peregra by an opposite treatment. 



In dealing with the different forms, I propose to place 

 them in sections, based upon the proportion the length of the 

 aperture bears to that of the whole shell. This plan is not quite 

 satisfactory, but is the one nK)st generally followed when any 

 arrangement of the varieties of the Lim/icece is attempted. 



Under the heads of the varieties described and figured, 

 I shall attempt to group together those named forms which 

 appear to have the greatest afiinity for each other, and thus 

 endeavour to reduce to some extent the inordinate number 

 of specialized forms. In doing this I do not wish to disparage 

 or depreciate the careful and accurate work of the learned 

 European conchologists, whose views as to specific limits are so 

 different from those held in this country, but only aim to point 

 out the actual affinities and differences which do exist and to 

 give accurate outlines of the more interesting forms, especially 

 those that have not hitherto been figured. In the present 

 paper I shall only describe and figure varieties in my own col- 



J.C, vi., Oct., 1890, 



