may, within uncertain fragmentary limits, be occasionally "con- 

 jectured " and its future very hazardly " guessed " at. VVe know. 

 unfortunately, nothing positive regarding the origin of any 

 living being in Nature, and can have no hope of lifting tlu 

 of the far future, which is probably one of the special attributes 

 of the Creator, not of His creatures. This being the case. I 

 consider that the history of a species is beyond the limits of 

 human science. All we can do is to study transient and variable 

 forms, not "species" in the general acceptation of the term. 



No attempt has been made by the author to establish the 

 affinities of the Campylodisci mentioned in this paper. This, as 

 well as full descriptions and a discussion of comparative charac- 

 teristics, is reserved for a future complete monograph, to which 

 these pages are only the prelude. Let me add that a verifica- 

 tion of the names arrived at by the use of the analytical tables 

 should be made by referring to published figures of the species 

 as indicated in the Synonymic Catalogue which immediately 

 follows this introduction. 



