PART I. PRINCIPLES INVOLVED IN DESIGNATING THE TYPES 

 OF GENERA OF PARASITES. 



INTRODUCTION. 



Cook (1900) has well .remarked that "botany without designation of 

 types is like geography without position," and the same remark applies 

 with equal force to zoology. The designation of the typical species of 

 genera is one of the most important points in nomenclature. 



Unfortunately none of the existing codes treats of the subject of type 

 designation in an entirely satisfactory manner. Unfortunately, also, 

 there is considerable diversity of opinion among authors as to the 

 methods to be followed in selecting the type. In rare instances 

 (Snellen), a systematist will deny the advisability of acknowledging 

 that a genus should have a type. Very commonly, more particularly 

 among earlier authors, the selection of generic types has been ignored. 

 Some authors consider that the selection of a type should be made 

 purely by rule, thus eliminating all subjective element; for instance, 

 by selecting the first species in the original list. Other workers con- 

 sider that a comparison of the original generic diagnosis with the orig- 

 inal specific diagnosis is the most important process to be considered. 

 Still other systematists are inclined to ignore the original diagnoses. 

 Some s} T stematists have attempted to formulate a definite series of 

 rules, to be followed seriatim. Others doubt the advisability of rules 

 to cover the subject and maintain that the entire process is one to be 

 governed by the particular case which arises for decision. Some 

 workers consider that the establishment of types is to be based pri- 

 marily upon anatomical study; others maintain it is to be based purely 

 upon a study of the literature. Several systematists have admitted 

 that they disliked to determine types, because it seemed impossible to 

 do so in such a way as to avoid polemic criticism. 



We have been requested by several authors, botanical as well as 

 zoological, to formulate our views on this subject, and it is partially 

 in compliance with these requests that the present paper is prepared. 

 A further reason for discussing the matter is that we consider it one 

 of the most important subjects in the entire field of nomenclature, and 

 we view the practice of failing to designate the type species as one of 

 the most fruitful sources of confusion in systematic writings. 

 10 



