NO. 2131. 



NEMATODE PARASITE.^ OF RODENTS— HALL. 



209 



is the largest and most prominent of the caudal papillae. The testis 

 extends anteriorly to a point more than tAvice the leng:th of the 

 esophagus from the anterior end. The transformation from the 

 vas deferens to the vesicula seminalis is strongly marked. 



Female T.o to 8.5 cm, long with a maximum thickness of over 2 

 mm. (fig. 273). The posterior extremity of the body terminates in 

 a blunt cone which rounds off almost hemispherically. The head 

 attains a maximum diameter of about 350 [;.. The phaiynx is about 



Fig. 272.— Protospirura ASCARoroEA. Posterior extremity of male. 



155 [JL long and the lumen is about 95 ^ wide. The esophagus has a 

 maximum length of about 5.2 mm. and a maximum thickness of 

 about 575 p.. The nerve ring is situated near the anterior extremity 

 of the esophagus, about 380 ^ from the anterior extremity of the 

 body. The intestine is constricted near its posterior extremity and 

 then expanded in a discoid structure which connects by a short 

 narrow tube with the anus (fig. 274). The anus is 1.37 to 1.46 mm. 

 from the tip of the tail. The vulva is a little anterior of the union 

 of the anterior and middle third of the body. The short muscular 

 vagina (fig. 275) extends posteriorly from the vulva for a distance 

 of about 515 pi,, where it meets a not so clearly delimited sphincter 

 region about 260 ;;. long. From this the common trunk of the 

 uterus, distended with eggs, extends a distance of 2.24 mm. and 

 forms the two divergent uterine branches. The anterior uterus 



10600"— Proc.N.M.vol.50— 16- 



-14 



