DETERMINATION OF GENERIC TYPES, ETC. 63 



In view of the fact that some men endeavor to consistently apply 

 page precedence, it is well for those of us who do not adopt it as a rigid 

 rule to at least follow it in all cases where it is a matter of indifference 

 to us which of two species is taken as type. A consistent adoption of 

 page precedence as a rigid rule may result in the designation of a 

 doubtful or even invalid species as type, because of the arrangement 

 of the species in a work; or since an alphabetical index to species may 

 be bound in some copies of a work in front, in other copies in back, 

 some authors might insist that one species is type, while other authors 

 would be consistent in insisting that another species is type. Still 

 other authors apply the principle only to the systematic portion of a 

 paper. As a rigid rule, page precedence seems to us to be unsafe, 

 furthermore, because its application may entirety misrepresent an 

 original author's idea and intentions. See also pp. 20, 24. 



If an author states that the types of his own genera should be 

 selected by page precedence, this method should of course appty to 

 his names. Thus, Bastian has written us under date of March 22, 

 1904, "that it might be taken as certain that the species of each genus 

 first described by me was to be considered as type of the genus, so 

 far as I knew it. In only a few cases is there any room for doubt as 

 to this." He then discusses the doubtful cases, and determines in 

 every instance the first species as type, stating that this or that species 

 ''was regarded as the type " or " was taken as the type." Fortunately, 

 therefore, Bastian's original intentions are now definitely known 

 regarding the types of his genera, and we consider it obligatory to 

 take his intentions in these cases, although in one instance we consider 

 the selection unfortunate. 



15. SEXUALLY MATURE FORMS TAKE PRECEDENCE OVER LARVAL OR IMMATURE FORMS. 



RECOMMENDATION. Species based upon sexually mature specimens 

 should take precedence over species based upon larval or immature forms. 



This recommendation needs no argument for helminthologists. 



16. PREFERENCE TO BE SHOWN TO SPECIES EXAMINED BY AUTHOR OF THE GENUS. 



RECOMMENDATION. All other things being equal, show preference to a 

 species which the author of a genus actually studied at or before the time 

 he proposed the genus. 



In general, it is natural that an author should have a clearer idea of 

 a species which he himself has studied than of one which he knows 

 only from a description written by some one else. And as a rule it 

 will be found that in proposing new genera an author has been influ- 

 enced more by his actual acquaintance with the organisms themselves 

 than by the description of animals which he has not seen. Although 

 exceptions to this proposition are not unknown, an author's original 



