THE GAPE- WORM. 77 



pool edges, in and around the drinking-vessels of the 

 fowls being also a favourite locality. 



The eggs hatch in from seven to forty days, ac- 

 cording as to whether the surroundings are favour- 

 able or not. 



These ova and embryos get taken up by the fowls 

 either off the ground or in the water. They then 

 develop direct into the worm in the tracheal reo-ion 

 of the fowl. The small embryo-worm grows rapidlv, 

 and soon becomes mature and the female united per- 

 manently to the male. They are often spread by one 

 bird devouring the worms coughed up by another. 

 Distribution from one area to another is carried on by 

 such wild birds as the Starling and Magpie, which are 

 both very largely infested with Syngamus trachealis. 

 Other hosts are the Sparrow, Partridge, Green Wood- 

 pecker, Martin, Linnet, Hooded Crow, and the Eook. 



Ehlers was the first to show that the ova develop 

 direct into the worm, no intermediate host beino- 

 necessary as hinted at by that great authority 

 Dr. Cobbold. Ehlers fed birds on Syngannis-oxa, 

 and in ten days he found coupled worms in them, 

 and seventeen females were present full of eggs. 

 Megnin again, in 1872, gave a parrot Gapes by feed- 

 ing it with ova from a pheasant. Numbers of times 

 I have convinced myself of the truth of these state- 

 ments by feeding quite healthy pullets with the 

 worms and ova, and thus producing the disease in 

 individuals quite free from it previously. 



It was never a case of the identical worms given the 



