208 BULLETIN 140, UNITED STATES NATIONAL MUSEUM 



Morphology. — Spiroptera (p. 205) : Mouth orbicular. 



Male unknown. 



Female 41 mm. long by 1.15 mm. wide. Anterior extremity of the 

 body sharply narrowed for a distance of 2.25 mm., a condition 

 attributed by Dujardin to contraction in alcohol. Tail acute. 



Life history. — Unknown. 



Distribution. — Europe (Austria) (Vienna)). 



The description is inadequate for a transfer of this species to any 

 other genus. Diesing (1851) states that it is more like an ascarid 

 than like a Physaloptera. Ortlepp (1922) includes it in his list 

 of species wrongly attributed to Physaloptera. The description was 

 based on a single specimen. 



Family DESMIDOCERCIDAE, new family 



Family diagnosis. — Spiruroidea (p. 162) : Forms with distinctive 

 larval characters maintained into adult life; both male and female 

 may be provided at tail end with a cluster of filiform papillae or 

 modifications of the same, the male not provided with caudal alae 

 or caudal papillae of usual type. Mouth with 2 lips, each lip 

 with 4 submedian papillae. Esophagus divided into distinct anterior 

 and posterior portions. 



Parasitic in respiratory tract of birds. 



Type genus. — Desmidocerca Skrjabin, 1916. 



When Skrjabin made a new genus, Desmidocerca, for his very in- 

 teresting new forms he did not place it except as in the suborder 

 Spirurata. The very distinctive characters of the spirurid larva 

 maintained throughout life, as shown in both the male and female 

 of his type-species, do not fit into any of the families as previously 

 made in the Spiruroidea. The present writer has therefore made a 

 new family for the genus. These forms are perhaps the most prim- 

 itive of the spirurids, their larval characters, indicative of their 

 ancestry, not having been lost in adult life, as in the other groups. 



Subfamily Desmidocercinae, new subfamily 



Subfamily diagnosis. — Characters of the family. 



Genus DESMIDOCERCA Skrjabin, 1916b 



Generic diagnosis. — Desmidocercinae (p. 208) : Very small nema- 

 todes. Head with 2 projecting lips and, posterior to each lip, 4 

 submedian papillae. Esophagus cylindrical, consisting of 2 por- 

 tions. Caudal extremity in both male and female of type species 

 provided with a clump of filiform papillae; in the second species 

 of the genus these are modified to lateral knobs in the female and 



