NO. 2131. NEMATODE PARAf^ITES OF RODENTS— HALL. 163 



infection Avith the adult worm when fed to sheep. This points to a 

 direct development without intermediate host for the worms in this 

 group. The fact that hmgworms have been found in newborn ani- 

 mals and in the fetus, suggests that the life history is not entirely a 

 simple one. 



Genus SYNTHETOCAULUS Railliet and Henry, 1907. 



^yonym. — /Stronr/yJus Mueller, 1780, part, of authors. 



Generic diagnosis. — Metastrongylinae (p. 162) : Body capillary. 

 Mouth with three lips. Posterior extremity of the body of the male 

 reinforced by a chitinous arc. Bursa with the ventro-ventral and 

 latero-ventral rays close together and parallel, and with the medio- 

 lateral and postero-lateral rays close together and parallel. The 

 dorsal rays are united in a thick trunk of quite disproportionate size. 

 Two punctate, striate, or pectinate spicules, slightly bent. Between 

 the spicules and at some distance anterior of the bursa is an unpaired 

 chitinous accessory structure forming an angle open to the rear. In 

 the bursa region are two paired chitinous accessory structures, elon- 

 gate and approximately parallel. Vulva a little in front of the anus. 

 Uteri convergent. Eggs without a trace of segmentation when ovi- 

 posited. Embryo with a tail prolonged by an undulate appendix. 



Type-syecies. — Synthetocaulaus pidmonalls (Froelich, 1802) Hall, 

 1916. 



ANALYTICAL KEY TO SPECIES OF SYXTHETOCAULLTS. 



1. Parallel accessory organs of male 33 ^ long Si/ntlietocaulus j)MJi)ionalis, p. 1G3. 



Parallel accessory orgaus of male 50 /x long Synthetocanlus rufescens, p. 166. 



SYNTHETOCAULUS PULMONALIS (Froelich, 1802) Hall, 1916. 



/Synonyms. — Filarla pulirhonalis Froelich, 1802 ; Strongylus retortae- 

 formis major Rudolphi, 1819; Filarla leporis pidmonalls Rudolphi, 

 1819; Capillaria puhno nails Kudolphi, 1819; Strongylus commutatus 

 Diesing, 1851 ; Filaria leporis jmlmonalis Froelich, 1802, of Diesing, 

 1851; Trlchosomum leporis Dujardin, 1815, of Diesing, 1851; Tricho- 

 somum leporis {pulvwnale) Diesing of Diesing, 1851; Filaria termi- 

 nalis Passerini, 1884; Synthetocanlus commutatus (Diesing, 1851") 

 Railliet and Henry, 1907. 



Specific diagnosis. — Synthetocaulus (p. 163): Body filiform. An- 

 terior extremity attenuated and head obtuse. Mouth with three lips 

 and with six very small circumoral papillae. The slender esophagus 

 is slightly dilated posteriorly. The intestine is dark broAvn and is 

 lined with polygonal cells. The excretory pore opens just behind the 

 posterior end of the esophagus (fig. 209). 



