242 



PARASITES OF THE DOMESTIC ANIMALS 



Heterakiasis of Chickens 



Family III. Heterakidae. Nematoda (p. 217).— This family, like 

 the Oxyuridae, is placed by some authors with the Ascaridse. The 

 t3Te-genus is Heterakis, of which two species infesting chickens are to 

 be described. 



1. Heterakis perspicillum (H. inflexa). Fig. 126. Heterakida 

 (p. 242).— The mouth has three lips of unequal size, the dorsal lip the 

 largest. The body is yellowish white. The caudal extremity of the 



Fig. 126. — Heterakis perspicillum: a, female; b, male; 

 c, Heterakis vesicularis. All natural size. 



male terminates obliquely, and is provided on each side with a mem- 

 branous wing and ten papillae. The two spicules are nearly equal. 

 On the ventral surface anterior to the anus there is a rounded sucker. 

 The caudal extremity of the female is straight, conical, and terminates 

 in a point. The vulva is located in the anterior part of the body. 



Length of female, 6-12 cm. (2 1/2-4 3/8 inches) ; male, 3-8 cm. (1 1/4- 

 31/8 inches). 



Eggs, elliptical, 75-80 microns in length by 45-50 microns in width. 



The species is common in the small intestine of the chicken, turkey, 

 and guinea fowl. 



2. Heterakis vesicularis (H. papillosa). Fig. 126. Heterakidae 

 (p. 242). — The mouth has three small lips of equal size. The body is 



