DETERMINATION OF GENERIC TYPES, ETC. 11 



Our general position on the subject may be summed up as follows: 

 Types should be determined for all generic names as soon as possible, 

 since a generic name without a definitely established type is always an 

 element of danger in both systematic and bibliographic zoology. 

 Although it does not seem possible to lay down any series of rules for 

 the determination of types which will meet with the approval of all 

 systematists, or which will not in some instances lead to rulings that 

 will arouse criticism on the part of some authors, still it seems justified 

 to adopt certain rules covering the subject and to carry them out con- 

 sistently, even at the risk of disapproval of other workers. These 

 rules should be objective so far as possible; recommendations (in dis- 

 tinction to rules) can not, however, be entirely avoided, since there 

 are some cases in which it hardly seems possible at present to exclude 

 entirely the subjective element. 



Satisfactory rules can be made which will govern a large percentage 

 (perhaps 80 to 90 per cent) of the cases. Any author who attempts to 

 determine types in the remaining cases will incur criticism from one 

 source or another, no matter what species he selects. 



In determining types for certain of the nematode genera, this has 

 accordingly been done with full knowledge of the fact that any person 

 who attempts work of this kind subjects himself to criticism, fre- 

 quently expressed in terms more vigorous than diplomatic. 



In discussing the principles involved, the parasites especially have 

 been held in mind, but the principles involved in helminthology are 

 the same as those involved in other fields of zoology. One can not, 

 therefore, plead for any exceptions in favor of helminthology, since 

 exceptions in this field invite exceptions in other fields, and are thus 

 both dangerous and shortsighted. The more exceptions admitted, 

 the less hope there is for eventually having an international nomen- 

 clature. Better it is by far that a temporary inconvenience be borne 

 than that exceptions be made in favor of any one group. 



GENERA OTHER THAN NEMATODES INCLUDED IN THIS PAPER. 



It has been found advisable to include in this list a few names which 

 do not belong to the Nematoda, but which have at one time or another 

 been used as or confused with nemathelminth names. 



TYPES DESIGNATED OR NOT DESIGNATED. 



For the generic names collected, an attempt has been made to deter- 

 mine the type in case the proper data were accessible. In some cases 

 in which we have hesitated, for various reasons, to definitely fix the 

 type species at present, species have been suggested with reserve 

 (preceding the specific name by " ?" or "probably") which it would 

 probably be best to take as type, so far as the data are accessible. 



