70 ILLINOIS BIOLOGICAL MONOGRAPHS [420 



Length, 10 to 16 cm. Breadth, 6 to 8 mm. 200 to 300 seg- 

 ments. 60 to 80 testes. In Arctomys sp., Turkestan. (See 

 Zschokke, 1888; and Stiles, 1896.) A. transversaria 



No information available. • (See Railliet, 1893.) A. restricta 



Genus Schizotaenia 



30. Genital pores regularly alternate. Testes posterior, except in 



occasional proglottids in one species. Less than 20 cm. 

 long _ m 31 



Genital pores irregularly alternate. Testes posterior, extending 

 uniformly across the median field. About 3 cm. long. Hosts, 

 Dicotyles albirostris and D. torquatus, Brazil. Not well 

 known, position not assured. (See Liihe, 1895.) 8. decrescens 



Genital pores unilateral. Size enormous, up to 120 cm. long, 

 and 7.5 cm. broad. Testes mostly on pore side 33 



31. Testes extending nearly uniformly across the median field in 



only two or three rows anteroposteriorly. Female glands 

 near the median line so that the ovaries of the two sides 

 overlap for most of their width „ _. 32 



Testes nearly all in the half that contains the genital pore. 

 Female glands far from the median line, the ovary not 

 reaching the median line of the proglottid. Hosts, Erethi- 

 zon dorsatus and E. epixanthus, North America. (See 

 present paper. ) „ S. variabilis 



Testes either extending across the median field, or in two 

 groups separated from each other by the vitelline gland; 

 in either case mostly on the side away from the genital 

 pore, where they are in six or seven rows in the antero- 

 posterior axis. Female glands quite large very near the 

 median line. Host, Oeomys breviceps, Oklahoma. (See 

 present paper. ) _ S. anoplocephaloides 



32. Length, 14 cm. Number of proglottids, about 280. Vitelline 



gland compact, formed of many small radiating lobes. 

 Walls of vesicula seminalis glandular throughout. Vaginal 

 walls glandular. Host, Hydrochaerns capybara, Brazil. 



(See von Janicki, 1906. )_ S. hagmanni 



Length, 3 to 4 cm. Number of proglottids, about 100. Vitelline 

 gland formed of a large median and a smaller lateral lobe. 

 Walls of vesicula seminalis not glandular, except at inner 

 end. Vagina ephemeral, walls not glandular. Hosts, 



