NO. 2131. NEMATODE PARASITES^ OF RODENTS— HALL. 163 



infection with 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,. — StrongyJi's 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 paFallel. 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. 



Tyye-syecies. — S ynthetocaulaus pulinonalis (Froelich, 1802) Hall, 

 1916. 



ANALYTICAL KEY TO SPECIES OF SYNTHETOCAULUS. 



1. Parallel accessory ortrans of male 33 a' long Synthetocauhis puJmonaUs, p. 163. 



Parallel accessory organs of mule 50 /x long Syntlietocaiilus ritfescens, p. 1G6. 



SYNTHETOCAULUS PULMONALIS (Froelich, 1802) Hall, 1916. 



Synonyms. — Fllarla pulmonalis Froelich, 1802 ; Strongylus retortae- 

 formis major Rudolphi, 1819 ; Filaria leporis -pulmonalis Rudolphi, 

 1819 ; Cajnllaria pulmonalis Rudolphi, 1819 ; Strong ylus commutatus 

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

 1851 ; Trichosomumj leporis Dujardin, 1845, of Diesing, 1851 ; Tricho- 

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

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

 Railliet and Henry, 1907. 



Specific diagnosis. — Synthetocaulus (p. 163) : Bod}^ 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 brown and is 

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

 posterior end of the esophagus (fig. 209). 



