56 BUREAU OF ANIMAL INDUSTRY. 



In case species are temporarily classified in such collective groups, 

 we believe their specific names should be entitled to priority when 

 they are definitely classified in their proper genera. 



12. TYPE BY ELIMINATION. 



RULE. The following species are excluded from consideration in select- 

 ing the types of genera: 



[(a) Species which were not included under the generic name at the time of 

 its original publication.] 



[(b) Species which were species inquirendae from the standpoint of the 

 author of the generic name at the time of its publication. (See p. 29.)] 



[(c) Species which the author of the genus doubtfully referred to it.] 



(d) Species which have subsequently been selected to serve as types for 

 other genera, unless this applies to all of the available species, in which case 

 the last species so selected becomes the type of the original genus; or unless 

 the species which the original author took as his type has been transferred, 

 in which case the original author's intentions should be carried out. 



[RULE. In case of Linnsean genera, select as type the most common or the 

 medicinal species.] 



RECOMMENDATIONS. The following species should be shown preference 

 in selecting the type, unless such procedure is contraindicated by the original 

 author's intentions or by practical considerations: 



(a) If the genus contains both exotic and nonexotic species from the stand- 

 point of the original author, the type should be selected from the nonexotic 

 species. 



[(b) If some of the original species have later been classified in other genera, 

 but not designated as their types, preference should be shown to the species 

 still remaining in the original genus.] 



[(c) All other things being equal, page precedence should obtain in select- 

 ing a type.] 



[ (d) Species based upon sexually mature specimens should take precedence 

 over species based upon larval or immature forms.] 



[(e) 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.] 



[(f ) Show preference to a species bearing the name communis, vulgaris, 

 medicinalis, or offlcinalis.] 



[(g) Show preference to the best described, best figured, best known, most 

 easily obtainable species, or of which a type specimen can be obtained.] 



[(h) Show preference to a species which belongs to a group containing as 

 large a number of the species as possible.] 



[(i) In parasitic genera select, if possible, a species which occurs in man or 

 in some food animal, or in some very common and widespread host.] 



In selecting the type of a genus for which no type has been desig- 

 nated or indicated, the first thing to do is to list all of the original 

 species of the genus. Assuming that a careful study of this list does 

 not result in showing that a type was originally determined by desig- 

 nation, implication, inclusion, etc., it becomes necessary to next estab- 

 lish whether any author has subsequently determined the ' ' type by 

 later designation." Assuming that the study is still negative in 



