DETERMINATION OF GENERIC TYPES, ETC. 57 



results, it is next necessary to determine what original species of the 

 genus are still available as types, and this of course involves a deter- 

 mination of t\\e species which are not available. 



ELIMINATION OP SPECIES INQUIREND^E. 



In the foregoing pages (p. 29) the stand has been taken that one 

 class of species, from the very nature of things, should be considered 

 unavailable as types, namely, species which the original author con- 

 sidered species inquirendse. Covering a second class of species, which 

 are almost universally considered as unavailable for types, the follow- 

 ing rule may be formulated: 



ELIMINATION OF DOUBTFULLY REFERRED SPECIES. 



RULE. No species is available as type of a genus if the original author 

 referred said species doubtfully or only conjectnrally to the genus in 

 question. 



Such a rule seems to be in accord with the best practices in sys- 

 tematic zoology, and seems so eminently justified that a special discus- 

 sion of -the rule appears scarcely necessary. 



It is clear that in selecting a type some species should be taken 

 which the author had particularly in mind as a typical representative 

 of the genus. If an author is in doubt as to whether a given species 

 belongs in the genus he is proposing, it is self-evident that he did not 

 consider it a typical representative species of the group and that he 

 had other species more particularly in mind in proposing the genus 

 and writing the generic diagnosis. Accordingly, the doubtful refer- 

 ence of a species to a genus is ipso facto a denial that that species is 

 type. 



For instance, in proposing and discussing the genus Lecithodendrium, 

 Looss (1896, 86) said : ' ' De ce groupe font partie, de plus, les Distomum 

 ascidia et ascidioides van Ben. et probablement aussi le Dist. Jieteropo- 

 rum Duj." Since Looss expressed this reserve regarding the classifi- 

 cation of D. heteroporum in Lecithodendrium, he certainly did not con- 

 sider it the type of his genus; in fact, this very reserve practically 

 amounted to a definite statement at the time the genus was proposed 

 that heteroporum was not in his mind the type. This example will 

 serve to illustrate quite a number of cases in various groups. See 

 also Euchromadora. 



Ruling out from further consideration all species inquirendse (from 

 the standpoint of the original author of a genus at the time of its propo- 

 sition), see page 29, and also all species originally placed in a genus 

 with reserve, with doubt, or by conjecture, we next come to the species 

 which from other causes should be eliminated from consideration. 



