operculum at each end (Fig. 61); S. bronchialis (goose, duck; larynx, 
trachea and bronchi), 80 to 90 by 60, with an operculum at one end. 
The eggs of Amidostomum anseris (goose, duck; esophagus, proven- 
triculus and gizzard) are 84 microns long by 50 microns wide and 
contain an embryo when deposited. 
The eggs of the worms belonging to the family Heterakidae of 
the superfamily Oxyuroidea are usually thick-shelled and are usually 
not yet segmenting when deposited. The dimensions of some of these 
eggs in microns are as follows: Heterakis papillosa (chicken, turkey, 
guinea fowl, peafowl, duck, goose; ceca; U. S.), 63 to 71 by 38 to 48 
Fig. 61. Syngamus trachealis. Eggs in various stages of development. Enlarged. 
From Neumann, 1909, after Railliet. 
(Fig. 62); Ascaridia perspicillum (chicken, turkey, guinea fowl; 
intestine; U. S.), 75 to 80 by 45 to 50; A. lineata (duck, chicken; 
intestine), 80 by 50; A. columbae (pigeon; intestine; U. S.), 60, 68, 72 
and 80 to 90 microns long, according to various writers, by 40 to 50 
microns wide. A member of the same family, Subulura differens 
(chicken, guinea fowl; intestine), has eggs which are almost spherical, 
59 microns long by 50 microns wide, containing embryos when 
deposited. 
The worms belonging to the superfamily Trichuroidea have lemon¬ 
shaped eggs as a rule. The dimensions in microns of the eggs of 
some of these worms are as follows: Capillaria retusa (chicken, 
56 
