300 



PARASITES OF THE DOMESTIC ANIMALS 



Fig. Itil. — Trichuris ovis. Egg. 

 x600. (After Ransom, Bull. No. 127, 

 Bureau An. Ind., U. S. Dept. Agr.). 



Fig. 160, 

 at left. * Vulva, xo 

 tice, Bull. No. 127, 

 Dept. Agr.). 



portion enlarged. The female 

 measures 35-50 mm. (1 3/8-2 

 inches) in length, the anterior 

 slender portion constituting 

 about two-thirds of the total 

 length. The length of the male 

 is 33-40 mm. (1 5/16-1 9/16 

 inch), the anterior part about 

 five-eighths of the total. 



The eggs are 52-56 microns 

 in length. 



The worm lives in the large 

 intestine of domestic and wild 

 hogs. Infestation occurs as in 

 the preceding species. Ap- 

 parently little disturbance is 

 caused by its presence. 



Trichuris depressiusculus 

 ( Trichocephalus depressiuscu- 

 lus). Trichinellidse (p. 299).— 

 The male and female are 45- 

 75 mm. (1 3y^4-3 inches) in 

 length, the slender esophageal 

 portion constituting the ante- 

 Trichuris ovis; male at right, female rior three-quarters. The spe- 



(After Ransom, from Cur- 

 Bureau An. Ind., U. S. 



cies resembles Trichuris ovis of 

 ruminants and Tr. dispar of 

 man. The spicule of the male 



may reach the length of 10 mm. (3/8 of an inch) and terminates in a 



sharp point. 



The eggs are 70-80 microns in length. The development is similar 



to that of the preceding species. 



This parasite inhabits the large intestine, usually the cecum, of the 



dog. Eggs taken up by dogs release their embryos within the digestive 



tract where they attain full development. The worms are often found 



