92 Mr. F. P. Cambridge— >%»2<3 



diagnoses or by tlie views and standpoints of later authors. 

 If he does not soon find himself writing to living authors for 

 their types and fixing upon types for those who are dead, 

 I shall be very much surprised. 



As to whether I or Dr. Dahl agree with or differ from any 

 other author as to the extent of his genus is of absolutely no 

 importance to anyone. Nor are the views, standpoints, or 

 concepts either of the original or any later author of any 

 importance either. We are, happily or unhappily, dealing 

 with names and the definite characters to be connoted by 

 them, and we want these characters permanently attached to 

 one or other name by means of a single type-species, so that 

 we can all, when we wish, go to the facts themselves and 

 understand what we are talking about when we use these 

 names. 



Names are the current coin in the realms of systematic 

 zoology, necessary for the interexchange of ideas as to the 

 facts; but until these names have a fixed and definite 

 character-value, chaos can be the only result of using them. 



But Dr. Dahl says " of course everyone is at liberty to 

 choose a type for his own private purposes. ^^ But authors do 

 not choose types for their private purposes ; their selections 

 usually appear in publications, and thus the confusion begins. 

 Students consult these publications in order to ascertain what 

 conception, for instance, they are to form as to a certain 

 genus. There may be four or five authors dealing with 

 a genus of ten or a dozen species, and the student is often 

 coui'ronted with three or four ditferent conceptions of the 

 same genus. Some authors will have made new genera 

 based on other authors' concepts of the original genus, each 

 one taking a different author's concept. Often, too, an 

 author's original concept of another author's genus will 

 itself change in course of time (as in the case of Salticas), 

 and students who have been basing new genera upon this 

 author's original conception find that they have been building 

 on a quick-sand. Other authors, totally unable to arrive at 

 any reasonable conclusion as to the original genus at all, 

 and finding that of later authors not one has the same con- 

 ception, simply ignore the whole question. They then 

 probably make another new genus, when several already 

 exist wliich would meet the case, if types had been definitely 

 selected ; or, still worse, they further increase the confusion by 

 adding to literature yet another concept of the original genus 

 of their own. ^Vhat we need is a definite type-species for 

 each generic name, so that everyone can go to the fact and 



