NO. 2258. TAENIOID CESTODES OF DOGS AND VATS— HALL. 59 



This tapeworm must be comparatively common in dogs in some 

 places in the United States, as the larval worms are not infre- 

 quently met with, especially in swine, in the meat inspection service 

 of the United States Bureau of Animal Industry. However, the 

 worm has only been reported by Curtice (1892^7), who collected it in 

 a dog from the pound in Washington, District of Columbia, and by 

 Welch (1890(7.), who developed the adult worm in the dog as the re- 

 sult of feeding experiments. It has been collected from dogs in 

 Alaska by Doctor Joss of the United States Bureau of Animal In- 

 dustry, its occurrence here being reported by Ransom (1915). 



Family MESOCESTOIDIDAE Fuhrmann, 1907. 



Synonym. — Mesocestoidae Ariola, 1899. 



Family diagnosis. — Taenioidea : Scolex without rostellum or hooks. 

 Suckers unarmed. A single set of reproductive organs in each seg- 

 ment. Genital pores located on the ventral surface of the segment 

 near the median line. Vagina opens in front of or beside the cirrus 

 pouch. Eggs in gravid segments inclosed in a single thick- walled 

 Ggg capsule. Adults in mammals and birds. 



Tyjye-genus. — Mesocestoides Vaillant, 1863. 



Subfamily Mesocestoidinae Luhe, 1894. 



Subfamily diagnosis. — Mesocestoididae : Characters of the family. 

 Type-genus. — Mesocestoides Vaillant, 1863. 



Genus MESOCESTOIDES Vaillant, 1863. 



Synonyms. — Monodoridium Walter, 1866; Ptychophysa Hamann, 

 1885a. 



Generic diagnosis. — Mesocestoidinae: Genital pores near the an- 

 terior fourth of the ventral surface. The uterus forms an elongated 

 median sac with wavy outline, irregularly constricted at certain 

 points, the single egg capsule forming at the posterior portion of the 

 uterus and of the segment. 



Type-species. — Mesocestoides amhiguus Vaillant, 1863. 



No kej^ has been written for the species of Mesocestoides^ for the 

 reasons given in the discussion of M. litteratus. 



MESOCESTOIDES LINEATUS (Goeze, 1782a) Railliet. 1893a. 



Synonyms. — Taenia lineata Goeze, 1782a; Holy sis lineata (Goeze, 

 1782a) Zeder, 1803a; Taenia canis lagopodu Rudolphi, 1810a; 

 (?) Mesocestoides litteratus (Batsch, 1786a) Dolley, 1894a/ Taenia 

 pseudoelliptica Baillet, 1863a; Taenia pseudo-cupumerina Baillet, 

 1863a/ Ptychophysa lineata (Goeze, 1782a) Hamann, 1885a. 



