NO. 1105. PROCEEDINGS OF THE NA TIONAL MUSE UM. 217 



lateral canals ; transverse uterus single with proximal and distal pouches; dorsal 

 canal 'between, ventral canal and nerve; stroblla may attain 112 mm. long by 5 to IS 

 mm. broad. Host : Marmot ( Arctomys inarmota), Europe. C. marmotm ( p. 172). 



22. Cirrus pouch -very large and prominent, may attain 1.12 mm. long by 0.32 mm. 



broad; pores at or near distal corner of lateral margin; female glands not far 

 removed from dorsal canal; several accessory ventral canals; strobila may 

 attain 80 cm. long by 15mm. broad. Host: Wild rabbit (Lepus cuniculus), 



Europe C. denticulata (p. 174). 



Cirrus pouch small, 0.24 mm. long; female glands considerably removed from dorsal 

 canal; dorsal canal lateral or dorso-lateral of ventral canal ; reccptaculum seminis 

 very large; segments imbricate; strobila attains 40 mm. long by 5.5 mm. broad. 

 Host: Prairie gopher (Geornys bursarius), North America.. C. prwcoquis (p. 181). 



23. Cirrus pouch about 1 mm. long, extends some distance median of longitudinal 



canals ; testicles arranged in a band in distal portion of median field, extend- 

 ing beyond ovaries from canal to canal; ovary some distance from longitudi- 

 nal canals; uterus single, with well-developed proximal and distal pouches; 

 strobila attains 40 cm. in length by 8 to 10 mm. in breadth. Hosts: Common 

 hare (Lepus timidus) and mountain hare (L. variabilis) Europe. 



C.pectinata (p. 184). 



Cirrus pouch not over 0.5 mm. long, extends scarcely median of lateral canals'; 

 uterus single or double in the same strobila. Hosts : Lepus, North America. 24 



24. Testicles in two groups, one for each ovary, extending laterally of ovaries but 



absent from median field ; strobila attains 57 mm. or more in length by 10 mm. 



in breadth. Host: Cottontail rabbit (L. sylraticus) C. perplexa (p. 189). 



Testicles in a band confined to distal portion of median field between the 

 ovaries; strobila attains 100 to 180 mm. in length by 10 mm. in breadth. 

 Host: Cottontail rabbit (L. sylvaticus) and marsh hare (L. palustris). 



C. variabilis (p. 190), 25. 



25. Strobila nearly always more than 3 mm. broad ; posterior flap of segments 



nearly straight; segments slightly imbricate: genital pore in about the 

 middle of the lateral margin. Host: Cottontail rabbit (L. sylvaticus). 



C. variabilis (p. 192). 



Strobila nearly always more than 3 mm. broad; posterior flap of segments 

 lobed; segments imbricate; genital pores generally in distal half of lateral 



margin. Host : Marsh hare (L. palustris) C. variabilis imbricata (p. 193). 



Strobila rarely over 2 mm. broad; posterior flap straight; segments not imbri- 

 cate; genital pores generally in distal portion of lateral margin, generally 

 double, occasionally single. Host: Cottontail rabbit (L. sylvaticus'). 



C. variabilis angusta (p. 193). 

 Andrya (European). 



26. Genital pores near posterior corner of segment ; prostatic gland elongate ; head 



about 1 mm. in diameter; testicles comparatively few in number, confined 

 chiefly to aporose side of median field; cirrus pouch 0.32 to 0.34 mm. long; 

 strobila attains 60 to 80 cm. in length by 5 mm. in breadth. Host: Common 



hare ( Lepus timidus), Europe - A . rhopalocephala (p. 155). 



Genital pores in about the middle, or in the distal half of the lateral margin; 

 prostatic gland round; head about 0.5 mm. in diameter; testicles about 50 in 

 number, scattered through entire median field; cirrus pouch 0.4 to 0.48 mm. 

 long; strobila attains 100 cm. in length by 8 mm. in breadth. Host: Wild 

 rabbit (Lepus cuniculus), Europe - ^- cuniculi (p. 158). 



DipylidiincB. 



27. Suckers unarmed - ** 



Suckers armed with minute booklets (with four exceptions known only in 



birds) 3 



28. Genital pores double ^ 29 



Genital pores single, irregularly alternate or unilateral 31 



