206 



PROCEEDINGS OF THE NATIONAL MUSEUM. 



VOL. 50. 



Fig. 267.— Protospirura muris. 

 Encapsuled larva from meal 

 •WORM. After Leuckart, 

 1876. 



men, and a maximum thickness of about 450 fi. It communicates 

 with the intestine by a large valve. An occasional constriction of 

 the intestine posterior of this valve gives rise to an appearance of the 

 anterior intestine which simulates an esophageal bulb. The nerve ring 

 is far forward en the esophagus as in the male. The anus is about 



520 ju, from the tip of the wedge-shaped dor- 

 sal termination of the tail. The vulva is a 

 little anterior of the middle portion of the 

 body, and is a rather elliptical depression. 

 From the vulva the vagina extends ill gen- 

 eral posteriorly, though it is somewhat 

 looped. The maximum length of the 

 vagina and oidjectors to the bifurcation 

 where the uterine branches originate is 

 about 1 mm. The uteri are divergent. The 

 anterior uterus extends forward about to 

 the posterior end of the esophagus. The 

 elliptical eggs attain a maximum diameter 

 of about 5G by 30 /-i, Avith a shell about 4 to 5 ;u, thick. They contain 

 an embryo when oviposited. 



Life historij. — Leuckart (1867) and Marchi (1871) have described 

 the life history of this worm. The eggs in the feces of the mouse 

 are eaten by meal worms, Tcnebrio species, and the embryos escape 

 and make their way to the body cavity. 

 In five weeks they develop to encapsuled 

 larvae (fig. 267) very similar to the larvae 

 of species of Gon^gylonema. 



Hosts. — Mus musculus, Epimys norvegi- 

 cus {Mus decwmanus)^ Epimys rattus 

 {Mus rattus)., Epimys alexandrinus {Mus 

 alexandrinus) , Epimys siporanus {Mus 

 siporanus), Apodemus sylvaticus {Mus 

 sylvaticus). 



Location. — Stom a ch . 

 Localities. — Austria (Vienna), Galicia, 

 Germany (Berlin, Brcslau, Greifswnld), 

 France (Renncs), Madagascar, island of 

 Mentawei, Brazil, Algeria, United States (Washington, District of 

 Columbia; Idabel, Oklahoma; Colorado Springs, Colorado). 



This species often occurs in mice in lai-ge numbers. Cobbold (1879) 

 states that he has seen a molise so heavily infested that it was un- 

 able to run. I have seen one case in which the empty stomach was 

 distended by a number of these worms Avhich ballooned the stomach 

 walls as so many clock springs might have done. 



Fig. 26S.— PROTOsriRtTRA muris 



[SriROPTERA BRAUNl]. BURSA. 



Enlarged. After von Lin- 

 stow, 1S97. 



