PARASITES OF ANIMALS. 



1 Of 



is the Filaria cystica Rudolplii, originally found in a Brazilian 

 fish (^Symbranchiis laticai(dus'). It is, therefore, probable that 

 the eggs or young embryos of E. gigas are swallowed by 

 fishes, and in their bodies develop into the larval form and be- 

 come encysted,, and if then swallowed by some mammal, 

 migrate into its kidneys to become sexually mature. The 

 frequency of these ]">arasites in those animals that feed chiefly 

 on fish, such as the otter, mink, and seal, renders this view 

 very probable. 



The Gape-tvorm of Chickens, etc., (^Syngamus trachealis 

 Siebold). Figure 82. 

 This parasite lives in the windpipe and bronchial tubes of 

 chickens, turkeys, pheasants, partridges, crows, wood-peckers, 

 and many other birds. In young chickens and turkeys it 

 Figiire 82. often proves very destructive, by filling up 



the air passages, and thus quickly killing 

 whole flocks. In some parts of this 

 country at least three-quarters of all the 

 young chickens and turkeys are some- 

 times destroyed by this parasite. The 

 worms are reddish in color and have a 

 smooth skin, but spiral depressions run 

 around the body, giving it a twisted 

 appearance. The reproductive organs 

 show through the skin, as slender, 

 whitish, convoluted tubes. The males 

 and females are almost invariably found united firmly to- 

 gether, as shown in the figures, the integument of the male 

 soon becoming organically united to that of the female, so 

 that the copulation is permanent or for life. The females are 

 very much larger than the males, becoming about three- 

 quarters of an inch in length, and one-sixteenth of an inch 

 in diameter. The anterior end, in both sexes, suddenly ex- 

 pands into a trumpet-shaped, concave disk, in the middle of 

 which the mouth is situated, surrounded by six small chitinous 

 lobes ; the posterior portion of the body of the female is more 



. Figure 82. — Syngamus trachealis Siebold ; a, male and female united, natural 

 size ; h, anterior part of female, enlarged ; c, male, enlarged. From Cobbold. 



