58 BUREAU OP ANIMAL INDUSTRY. 



RESTRICTED AND UNRESTRICTED ELIMINATION. 



RECOMMENDATION. If the genus contains both exotic and nonexotic 

 species from the standpoint of the original author, the type should be selected 

 from the nonexotic species, unless such procedure is contraindicated by the 

 original author's intentions. 



It will be seen from page 17, that the A. O. U. Code distinguishes 

 between restricted and unrestricted elimination. For examples of the 

 two processes the reader is referred to page 17. 



So far as the Linnaean genera are concerned, it must be admitted 

 that there are certain advantages in restricted elimination, and so far 

 as general theory is concerned there are advantages in this process 

 when applied to later genera. There are also, however, difficulties 

 involved, and at present it would seem better to view restricted elimi- 

 nation as a recommendation rather than as a rule. 



ELIMINATION OF SPECIES SELECTED AS TYPES OF OTHER GENERA. 



RULE. Any species of a genus which has been selected to serve as type for 

 a later genus is excluded from consideration in selecting the type of the 

 earlier genus, unless this applies to all of the available species, in which case 

 the last species so selected becomes the type of the original genus. 



In not a few genera the type species has been consciously or uncon- 

 sciously determined by the transfer of all but one of the original avail- 

 able species to serve as types for new genera. In such event it is in 

 accordance with practice and rules to accept the remaining species as 

 type; or in case several species have not been- thus eliminated it is 

 customary to restrict the selection of type to these species, thus 

 excluding from consideration all species which have been selected as 

 types for more recent genera. 



As examples of genera of this kind cited in the present paper, we 

 may mention the following: 



Spttiphera Bastian, 1865, contained the following species: 

 elegans. 



insequalis, type of Hypodontolaimus, 1888. 

 robusta, type of Halichoanolaimus, 1888. 

 costata, type of Monoposthia, 1889. 



By the principle of elimination of species as types of other genera, 

 elegans remains as type of Spiliphera. This case agrees with page 

 precedence, and also with Bastian's original intentions, for he adopted 

 the custom of placing his type as the first species. 



Theristus Bastian, 1865, contained the following species: 



acer, type by elimination, author's intention, and page precedence. 

 velox, type of Penzancia, 1889. 



In some cases it is nevertheless necessary to select as type a species 

 of the original genus which has been selected as type for a more 

 recent genus. Two kinds of cases may arise, namely: 



