152 GUPPY : MOLLUSCA OF GULF OF PARIA. 



As regards the references to figures, I have generally selected 

 such as portray the species fairly, and where possible I have 

 chosen those most easily accessible to students; only citing the 

 more expensive and larger works on conchology where the ordinary 

 manuals failed me. 



In the synonymy the names quoted may not, in all cases, 

 have been originally intended for the species under which they 

 here stand, but may have been incorrectly applied by some author. 

 Owing to the close resemblance of some species of the eastern 

 hemisphere to western ones, it has often happened that one name 

 has been used for two distinct shells; and I am not sure that we 

 have yet in all cases avoided the errors traceable to this source of 

 confusion. 



The principle on which the authorities are cited is that the 

 specific names are assigned to the author who first described the 

 species, and to the one who first adopted a particular collocation 

 of generic and specific names. This principal has been generally 

 acted up to by conchologists; but it is to be regretted that many 

 writers on natural science have followed a different course, thereby 

 introducing unnecessary disorder into nomenclature. The want 

 of a definite enunciation of the rule may be somewhat to blame 

 for this: I propose the following — "The author's name appended 

 to a specific name is to be regarded as the authority for the 

 specific name only." 



The classification I have adopted is that I have used in my 

 own cabinet. It is in the main based upon that of Woodward, 

 by far the best ever published. Some of my innovations may 

 seem hazardous, but I have never departed from my model 

 without the most substantial reasons. I have long had in 

 preparation a paper on this subject, but have not yet found the 

 leisure to complete it. I can hardly say anything too strong 

 against the systems devised by various conchological writers, as 

 they seem to be founded on the most arbitrary and artificial 



J.C, ii., May, 1379 



