46 BUREAU OF ANIMAL INDUSTRY. 



on basis of this publication, as it seems clear that the authors admitted 

 other species to the genus. Bastian, 1865c, clearly took terricola as 

 type of Rhabditis, as he eliminated aceti and glutinis to Anguillula 

 and tritici to Tylenchus, and he further speaks of "the typical Rhab- 

 ditis terricola" which probably refers to terricola as type. Schneider 

 (1866,148) rejected the name Rhabditis on the ground that its rela- 

 tions to Pelodera and Leptodera were so complicated. His P. teres 

 is interpreted by Railliet as synonymous with R. terricola; he elimi- 

 nated aceti and glutinis to Leptodera and tritici to Anguillula. 



Thus, if we try to settle the type of Rhabditis on the principle of 

 elimination, the citation of Gervais & van Beneden might be inter- 

 preted as a designation of aceti as type, yet this interpretation is by 

 no means free from objection. The exclusion of tritici from further 

 consideration as type, on basis of Gervais & van Beneden, would also 

 be open to question in the minds of some authors. If we adopt unre- 

 servedly the principle of type by later designation, as at present 

 provided for by the International Code, Bastian's action of 1865 would 

 settle the point that terricola is the type of Rhabditis; and as stated 

 above, this ruling would agree with the ruling by page precedence. 



Rhabditis is thus seen to be the first case in this discussion in connec- 

 tion with which the principle of " type by inclusion " is seriously con- 

 traindicated by existing rules; had Bastian not designated terricola as 

 type, we would now designate glutinis as such on the ground of type 

 by inclusion, but in view of Bastian's designation, type by inclusion 

 is perhaps not admissible in this case. See axiom 2, p. 24. 



Trichosoma Rudolphi, 1819a, 13, was deliberately proposed as a new 

 name for Capillaria, 1800, and included both of the original species 

 of Capillaria', both of these species have been retained in Trichosoma 

 by Dujardin (1845a), Diesing (1851a, 1861a), and Stossich (1890). 

 Neither of them appears to have been made the type of other genera, 

 so that the principle of elimination does not seem to come into consider- 

 ation. If the case is decided on page precedence, brevicolle, 1809, 

 becomes type of Trichosoma. This species is capillaris, 1819, renamed, 

 which is " type by virtual tautonymy " of Capillaria. It would also 

 be " type by inclusion" of Trichosoma. 



Triodontophorusljooss, 1902, is Triodontus, 1900 (not 1845), renamed, 

 hence would take the same type; for neither genus was a type origi- 

 nally named, but Looss has since designated serratus as such. 



Helminthologists, after studying the examples given above, will 

 probably admit that the principle of type by inclusion is in accord 

 with the general spirit of the Law of Priority. That it seems Draco- 

 nian in some cases can not be denied, but it certainly greatly simplifies 

 the method of determining types in not an inconsiderable number of 

 genera and has the great advantage of permitting their determination 

 on the basis of the original publication, thus reducing the number of 



