1909.] TAPE-WORMS OF THE RED GROUSE. 300 
becomes very much larger. The lumen of the lateral canals 
increases and the transverse duct which unites them at the 
posterior end of each proglottis swells out amazingly. From 
being a slender duct it enlarges to a great spherical chamber, 
of which the sides, which will rupture when the proglottis drops 
off, are extremely thin (Pl. LIX. fig. 13 & Pl. LX. fig. 14). 
When the ova are squeezed out of a living ripe proglottis of 
D. urogalli, they present the appearance shown in Pl. LIX. fig. 12. 
A more highly magnified view is shown in Pl. LX. fig. 15. Hach 
ege contains a six-hooked embryo which is much smaller than 
the egg-shell. Besides the six-hooked embryo, the egg-shell 
contains two or three spherical bodies usually of about the same 
diameter as the embryo, but sometimes smaller. These are 
apparently yolk-spheres in course of absorption; the remainder 
of the ege-shell isempty. The six hooks, arranged in three pairs, 
have a characteristic shape shown best in P]. LX. fig. 16. The 
shape is similar to that of the hooks figured in the sketches 
of Davainea erabryos in Blanchard’s article * 
The genus Davainea occurs in many birds, Cursores, Galli- 
nace, Columbine, &c., and much more rarely, in the form of 
Davainea madagascariensis (Day.), in the intestine ofman. Little 
is known of their second hosts; they are usually believed to be 
insect larvee, centipedes, or land mollusks. Grassi and Rovelliy 
consider the intermediate host of the D. proglottina of the common 
fowl to be Limaw cinereus, L. agrestis, and L. variegatus. In this 
case the cysticercoid is fully developed in the slug within twenty 
days. If theslug be swallowed by a fowl the cy Sticereoid becomes 
adult at the end of eight days. We have up till now sought for 
the cystic form in Limax flavus without success. 
Davainea echinohothridat, which is possibly a synonym of 
D, tetragona, causes a nodular disease in poultry §, a condition 
liable to be mistaken for tuberculosis. This disease was first 
recorded in the United States by Moore (1895) ||, from whose 
article the following extracts are made :— 
“The nodules were invariably more numerous in the lowest 
third of the small intestine. They occasionally appeared, 
however, in small numbers in both the duodenum and colon. 
The larger and to all appearances older nodules were found in 
the ileum near the ceca. 
“Tn the badly affected portion the nodules gave the appearance 
of closely set protuberances, varying in size from barely per- 
ceptible areas of elevation to bodies 4mm. (+ inch) in diameter. 
In some instances they appeared to overlap oneanother. When 
separated by a band of normal tissue they were round or some- 
what lenticular in form. In the latter case the long diameter 
* Mém. Soc. Zool. France, iv. 1891, p. 420. 
+ Centrbl. Bakter. iii. 1888, p. 172. 
+ B. H. Ransom, ‘Manson’s Eye Worm of Chicken, &c.,’ Bureau of Animal 
Industry, U.S.A., Bulletin 60, 1904. 
§ D. HE. Salmon, y Tapeworms of Poultry,’ Bureau of Animal Industry, U.S.A., 
Bulletin 12, 1896. 
Ie WieeAs Moore, Bureau of Animal Industry, U.S.A., Circular I1I., 1895. 
