52 BUREAU OF ANIMAL INDUSTRY. 



(probably overlooked by Dujardin) was also available. That Dis- 

 pharagus had no raison d'etre is therefore clear, and the least that can 

 be done is to apply to it the Law of Priority, according to which 

 Dujardin should have used Oystidicola, from his systematic point of 

 view. He says, however, that "almost all of the species" which he 

 unites in Dispharagus are "entre les tuniques de 1'estomac ou du 

 gesier des oiseaux," so that it is only fair to follow, if possible, the 

 De Candolle principle (see below, p. 65) to confine Dispharagus to the 

 greatest number of species possible. This would eliminate Oystidicola 

 in favor of the antkuris group. But anthuris is the type of Anthuris, 

 1819, hence, Anthuris takes priority over Dispharagus, even from 

 Dujardin's systematic point of view. One is therefore brought to the 

 same point, but by a more indirect method, of suppressing Dispharagus 

 in favor of Anthuris, and taking anthuris as type. Anthuris, how- 

 ever, is Acuaria renamed, and Spiroptera is also Acuaria renamed, 

 hence, on basis of the type species, Acuaria, Anthuris, Spiroptera, 

 and Dispharagus should all be synonyms. 



This leaves the generic name Cheilospirura (type hamulosa, see 

 p. 93) available for the species at present included by more recent 

 authors (Stossich, 1891; Railliet, 1893) under Dispharagus. 



Authors who do not accept "type by inclusion" should notice that 

 Stossich (1891) in his revisions recognizes only five of Dujardin's spe- 

 cies as valid members of this genus, namely, anthuris, attenuatus, lat- 

 iceps, nasutus, and quadrilobus, and confines the genus to parasites 

 from the gastroenteric region of birds. As laticeps and quadrilobus 

 seem to have been placed here by conjecture, both of these should, if 

 possible, be avoided as type. Accordingly, authors who reject "type 

 by inclusion" would probably select either anthuris, attenuatus, or 

 nasutus as type. 



In most of the cases thus far mentioned under the nine headings 

 (pp. 25-52), the type of the genus seems to us to be either clearly 

 determined in one way or another in the original publication ; or at least 

 it is restricted to certain of the species. We now pass to 



B. GENERA FOR WHICH TYPES HAVE BEEN SELECTED IN LATER 

 PUBLICATIONS. 



10. TYPE BY SUBSEQUENT DESIGNATION. 



RULE. If an author, in publishing a genus with more than one ralid 

 species, fails to designate or to indicate its type, any subsequent author 

 may select the type, and such designation is not subject to change. 



This canon is a logical corollary of the law of priority, but it is of 

 course assumed that the second author has correctly selected as type 

 some species which was available as such. If he has selected a species 

 which was not available, his selection is not binding. 



