NO. 1105. PROCEEDINGS OF THE NATIONAL MUSEUM. 231 



PLATE XVIII. 

 Cittotcenia perplexa, from the Cottontail Rabbit (Lepus sylvaticus). 



FIG. 1. Strobila with head, natural size. No. 1126, U.S. N.M. 



2. Anterior portion of strobila enlarged to show the general appearance. No. 



1138, U.S. N.M. Zeiss, 4^a* 5. 



3. Ventral view of a single segment, showing nerves, canals, cirrus-pouch, vasa 



deferentia, testicles arranged in two groups, single uterus, two ovaries 

 and vitellogene glands. No. 1131, U.S. N.M. 

 Drawn by Haines. 



PLATE XIX. 

 Cittotcenia variabilis; Cittotcenia variabilis angusta. 



FIGS. 1-12. Cittotcenia variabilis, from the Cottontail Rabbit (Lepus sylvaticus). 



1. Strobila, natural size. 

 2-7. Six views of heads. 



8. Very young specimen. 



9. Very young specimen with beginning segmentation. No. 1373.7, U.S.N.M. 



10. Ventral view of segment in which uterus is not developed. No. 1162, 



U.S.N.M. Zeiss, 4-a* 10. 



11. Ventral view of segment with single uterus. No. 1207, U.S.N.M. Zeiss. 



4-a* 10. 



12. Ventral view of segment with two uteri, only one of which is well 



developed. No. 1162, U.S.N.M. Zeiss, 4-a* 10. 



13-14. Cittotcania variabilis angusta, from the Cottontail Rabbit (Lepm sylvaticus). 

 Two strobilso, natural size. For a figure of segments from fig. 14 (No. 

 119, U.S.N.M.), showing both double and single genital pores, see Stiles, 

 1895. 

 Drawn by Haines. 



PLATE XX. 

 Cittotcenia variabilis, from the Cottontail Rabbit (Lepus sylvaticus). 



FIGS. 1-5. Segments showing variations. All ventral views, except fig 1. Nos. 1154, 

 1122, 1125, 1127, 1152, U.S.N.M. Enlarged about 15 times. Zeiss, 4-a* 10. 

 Drawn by Haines. 



PLATE XXI. 

 Davainea retractilis, from the Arizona Cottontail Rabbit (Lepus arizonce). 



FIG. 1. Head enlarged. No. 1195, U.S.N.M. Zeiss, 4-16. 



2. Retracted sucker of same, greatly enlarged. 



3. Segments showing unilateral pores, longitudinal nerves and canals, and 



median female anlage. No. 1192, U.S.N.M. Zeiss, 4-16. 



4. Older segments of same strobila, showing testicles. 



5. Gravid segment showing one egg in each egg capsule. No. 1188, U.S.N.M. 



6. Egg capsule with egg. 



Drawn by Haines from poorly preserved specimens. 



PLATE XXII. 



Davainea retraclilis ; Davainea contorta; Davainea salmoni. 



FlG. I. Davainea retractilis, from the Arizona Cottontail Rabbit (Lepus arizonm). 



Transverse section through gravid segment. Zeiss. 4-16. 



2. Segment of Davainea contorta, from the Common Indian Pangolin (Manis 

 pentadactyla}'. h., testicle; u., uterus: ve., vas efferens; vd., vas deferens; 

 ci., cirrus; v., vagina; k., ovary; d., vitellogene gland. After Zschokke, 

 1895, fig. 2. 



