DETERMINATION OF GENERIC TYPES, ETC. 29 



worms namely, for the Strongylus contortus group (see Hsemonchus) 

 which is allied to but quite different from the original type. 



In cases of this kind the policy to be followed seems not to admit of 

 any hesitation. One should immediately revert to the original type, 

 returning S. equinus to the genus Strongylus. 



Such action will probably not meet with the approval of those who 

 oppose the Law of Priority, but consistency certainly demands a uni 

 form application of the principle involved. 



2. GENERA ORIGINALLY PUBLISHED WITH ONLY ONE VALID SPECIES, BUT ALSO WITH 

 ONE "OR MORE SPECIES INQUIREND.E. 



In several cases authors have published a genus with only one species 

 which they recognized as valid, but they have added to the genus one 

 or more species which they looked upon as species inquirendsz. Two 

 views might be advanced regarding such cases: 



First, it might be maintained that since the author was in doubt 

 regarding the validit}^ of certain species, but not regarding one species, 

 he must have had the one valid species especially in mind in proposing 

 the genus, while the insertion of the doubtful species was an after- 

 thought. Such an interpretation would very probably cover the 

 majprity of cases, but circumstances can be imagined which would call 

 for a modification of this view. Thus, an author might notice some 

 variation in certain specimens which might lead him to the view that 

 these possibly represented a species distinct from the one he recog- 

 nized as valid. This second species might, however, contain all the 

 characters he considered as generic and as found in the valid species. 

 In this case the doubtful species might be, in his eyes, just as impor- 

 tant, viewed from the generic standpoint, as the valid species. Cases 

 of this kind, however, would probably represent exceptions. 



Second, it might be maintained by authors who attach very great 

 importance to "elimination" that if any author selected the valid 

 species (from standpoint of the original author of the genus) as type 

 of a new genus, or transferred it to another genus, the t} 7 pe of the old 

 genus would have to be selected from the species inquirendpe. 



Personally we prefer the first interpretation, and would suggest the 

 general adoption of the following: 



RULE. The type of a genus (containing from the standpoint of its author 

 both valid and doubtful species) must never be selected from any species 

 which the original author of genus clearly designated as species inquirendse 

 at the time of the publication of the genus. 



NEMATODE GENERA OF THIS CLASS. 



The following genera in this paper come under the class now under 

 discussion:, 



Cosmocerca Diesing, 1861a, 645; type by present designation, ornata. 

 arnata considered valid by Diesing, 1861a, 645. 

 commutata given as species inquirenda by Diesing, 1861a, 645. 



