40 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 89 



Galeb, 1878); Aorurus Leidy, 1854 (syn. Strepiostoma Leidy, 1854; 

 syn. Blattophila Cobb, 1920). 

 Subfamily Syphaciinae. 



Genus: Aiigra Travassos, 1929. 



KEY TO SUBFAMILIES OF THE OXYURIDAE 



1. (2) Males without a gubernaculum Oxyurinae 



2. (i) Males with a gubernaculum Syphaciinae 



Here are united most of the known one-spiculed forms of the 

 Oxyurata, with numerous genera and species in both Vertebrata and 

 Invertebrata. The idea of separating them from other Oxyurata be- 

 longs to Travassos (1930). The further division as proposed by 

 Walton (1929) and Travassos (1930) would be difficult to follow 

 without a more complete consideration of the subject. The old divi- 

 sion proposed by Raillet and Henry (1916) and followed by Yorke 

 and Maplestone (1916) should therefore be accepted at this time. 



Orders ASCARIDATA, SPIRURATA, FILARIATA, 

 DIOCTOPHYMATA and TRICHURATA 



Parasitism always transforms an animal. The free-living stages 

 of the Strongylidae saved for us the evidence of their true nature ; it 

 is probable that because of the semisaprozoic life of the Oxyurata 

 they conserved traces of typical resemblance to the Anguillulata. But 

 the other parasitic orders do not possess free-living stages and are 

 more specialized in their parasitic life.* Thus little could be said 

 about their relationships. 



The comparatively small and highly specialized groups of Dioc- 

 tophymata and Trichurata could be considered as very isolated and 

 natural. The relations between the other orders seem to be not as 

 yet worked out. The Spirurata will probably be subject to most 

 modifications. But the wisest course for the moment would be to 

 keep all the three separate as Yorke and Maplestone have done. 



Wiilker (1929) has recently suggested a direct relation between 

 the Ascaridata from marine fishes and some free-living groups, thus 

 assuming an evolution of this order independent from other para- 

 sitic orders. But it is highly probable that the Ascaridata have had 

 a different mode of evolution, probably a much longer one and one 

 bound with some other parasitic groups. 



CONCLUSION 

 In the writer's opinion the classification of today, especially that 

 of the lower groups, is in reality the same as it was in the time of 



* An exception are the free-living larvae of Camallaniis, but these have 

 never been studied in detail. 



