62 BUREAU OF ANIMAL INDUSTRY. 



.no theoretical grounds are at present apparent for rejecting Ascaris 

 lumbricoides as type species of Ascaris. 



Sclerostoma Rudolphi, 1809, contained 2 species: 

 equinum, which is type for Strongylus, 1780. 

 dentatum, transferred to CEsophagostomum, 1861 = (E. subulatum, 1861, type. 



In this case equinum is also "type by inclusion." 



Liorhynchus Rudolphi, 1801, contained 



Ascaris tubifera Fabricius, 1780; to Echinorhynchus by Zeder, 1803; returned to 



Liorhynchus by Rudolphi, 1809. 



Ascaris truncata Rudolphi, 1793; probably type of Liorhynchus. 

 Ascaris pulmonalis "Gceze;" equals nigrovenosum, type of Rhabdonema, 1883. 

 Gcezia inermis Zeder, 1800; to Cochlus by Zeder, 1803. 

 Oncholaimus Dujardin, 1845, contained 



attenuatus Dujardin; to Enoplus by Diesing, 1851; returned to Oncholaimus as 



type by Bastian, 1865, and de Man, 1886, 9. It should probably be accepted 



as type (seep. 121). 



fovearum Dujardin; to Mononchus by Bastian, 1865. 

 muscorum Dujardin; to Mononchus by Bastian, 1865. 



14. TYPE BY PAGE PRECEDENCE. 



RECOMMENDATION. All other things being equal, page precedence 

 should obtain in selecting a type. - 



Several authors have raised page precedence to the rank of an iron- 

 clad law. They argue that the first place a specific name is found 

 combined with a generic name represents the first publication of a 

 name, hence that the species in question necessarily represents tbe 

 type in accordance with the spirit of the law of priority. They fur- 

 ther advance the point that page precedence is absolutely objective, 

 hence subjective opinions are eliminated, and every zoologist would 

 necessarily select the same species as type. In their position no dif- 

 ference in principle is acknowledged between two separate publica- 

 tions, on the one hand, and, on the other hand, two separate pages in 

 one and the same publication, or two separate lines on the same page, 

 or two separate words on the same line. The logical deduction from 

 their position is that every genus should be viewed as having had its 

 type determined in its original publication. 



It must be admitted that there are certain very great advantages in 

 this rather Draconian point of view. Still it may lead to the very 

 confusion it seeks to avoid, and it may give rise to complications 

 which could just as easily be avoided. In several cases in nematodes 

 it would make as type a species based upon the female alone, although 

 the author had described the male for other species. In view of the 

 importance of the male in classifying nematodes, helminthologists will 

 doubtless be rather reserved in admitting page precedence to higher 

 rank than a recommendation to be followed when all other factors are 

 equal. 



