Introduction YU 



In all cases where the date is doubtful and cannot be definitely 

 ascertained, the date figures are enclosed in brackets [ ], or have some 

 other distinguishing mark — ^.^., ? — placed against them\ 



In the case of plates appearing before the text, the date of each is 

 given if ascertainable (e.g., Schreber's ' Saugthiere'), but in no case 

 is the date of a plate accepted in preference to the date of text, for the 

 reasons vvhich follow : — 



The figure depicted on a plate may, ,or may not, be the drawing 

 intended by the author ; it is the work of the artist, who is also 

 responsible for the descriptive legend. In numerous instances the 

 descriptive legend on a plate is quite erroneous, and has been re- 

 pudiated by the author in his text. Until the text descriptive of 

 a plate appears, the names on the plate must be considered as 

 nomina nuda, and it is open to anyone to describe and rename such 

 nomina nuda. 



The following are the reasons for arranging the work under species 

 and not under genera, as in the ' Index Kewensis': — 



1. No synonymy of species is attempted : that depends on the 

 idiosyncrasy of the systematist. 



2. Any attempt at specific synonymy would be opposed to progress, 

 as experience shows that vast changes may take place in a single year. 



3. An arrangement under species permits of a generic synonymy, 

 for by running the eye down the second column of the printed work, 

 it will be possible to ascertain the various generic names with which 

 a particular species name has been connected. 



It is likely that many cases of apparently duplicate entries will 

 turn out to be so in fact, but the entries are given because it is by no 

 means clear from the diagnoses or remarks of the authors that they 

 are treating of a genus or species that has appeared before in litera- 

 ture. It is for the specialist to decide. 



All trivial names are entered as if they were masculine, e.g. 

 nigra will be found under niger 

 afrum „ „ afer 



abdominale „ „ abdominaHs. '''"'!' 



It is obvious that no other arrangement is possible if we wish to 

 preserve the history of a species ; but cross-references are given when 

 the feminine and neuter forms of the trivial word vary so much as to 

 obscure it to those, who, like myself, are unfamiliar with the dead 

 languages. 



1 It must be remembered that in every case the date given in the entries refers to \}a.t page, 

 so far as the compiler's researches have enabled him to decide it. 



