20 Tapeworms from Ostrich 
KEY TO SPECIES OF DAVAINEA— continued 
4 + 
4. 
Eggs singly in parenchyma .... 
. • (o) 
_i_ 
Egg-capsules contain several eggs . 
• • (12) 
• 
5. 
Rostellar hooks 34, 21—23/x long 
D. oligocantha Fuhr. 
Rostellar hooks over 100, under 18/x long 
. • (6) 
6. 
Testes less than 20. 
. • (7) 
Testes more than 20. 
• • (9) 
7. 
Rostellar hooks 14-16 /j, long .... 
D. anatina Fuhr. 
Rostellar hooks 9/i long. 
• • (8) 
8. 
Length -85 mm. 
D. minuta Cohn 
Length 150-200 mm. 
D. magnicoronata Fuhr. 
9. 
Rostellar hooks 7—11 /n. long, testes 20-30 
. . (10) 
Rostellar hooks 16—18/x long, testes 40-50 
. . (ID 
10. 
Cirrus-sac -24 mm. long. 
D. columbae Fuhr. 
Cirrus-sac *15 mm. long. 
D. cesticillus (Molin) 
11. 
Egg-capsules extend laterally beyond excretory 
vessels. 
Egg-capsules not extending laterally beyond 
ex- 
D. polyuterina Fuhr. 
cretory vessels. 
D. nana Fuhr. 
12. 
Testes less than 20. 
. • (7) 
+ + 
Testes more than 20. 
• • (13) 
13. 
Rostellar hooks 70. 
D. crassula (Rud.) Fuhr. 
Rostellar hooks over 150. 
• • (14) 
Rostellar hooks 800 . 
D. circumvallata (Krabbe) 
14. 
Rostellar hooks 21 p long. 
D mutabilis Ruth. 
Rostellar hooks IQp long. 
• • (15) 
15. 
3-4 eggs per egg-capsule. 
D. laticanalis Skrj. 
+ 
+ + 
8-12 eggs per egg-capsule. 
D. microcotyle Skrj. 
D. spinosissima v. Linstow. 
D. elongata Fuhr. 
(The literature of the following species not being accessible to me, they are not included 
in the above key: D. proglottina var. dublanensis Kowalewski, 1905; D. cacatuina Johnston, 
1912; D. conopophilae Johnston, 1912; and D. vagintivasus Skrjabin, 1914.) 
In addition, lack of adequate description prevents the following species from being 
included: D. asiatica von Linstow, 1901; D. australis (Krabbe, 1869); D. brachyrhnycha 
(Creplin, 1853); D. celebensis von Janicki, 1902; D. circumcincta (Krabbe, 1869); D. difformis 
(Rudolphi, 1819); D.tmperus Skrjabin, 1914; D. globocephala Fuhrmann, 1909; D.longicollis 
(Molin, 1858); D. macrocirrosa Fuhrmann, 1909; D. sp. Parona, 1909; D. sp. Johnston, 
1912; D. sp. Johnston, 1912; D. sp. Douthitt, 1916; D. sp. Vevers, 1920; D. sp. Vevers, 
1920; D. sp. Meggitt (present paper). 
LITERATURE. 
Ackert, J. E. (1918). On the life-cycle of the fowl cestode Davainea cesticillus (Molin). 
Journ. Parasitol. v. 41-43. 
- (1919). On the life-history of Davainea tetragona (Molin), a fowl tapeworm. Journ. 
Parasitol. vi. 28-34. 
