155 to 162 microns long by 82 to 90 microns wide, thickened at one 
pole and operculated at the other. Schistosomes, a group of flukes 
inhabiting the blood-vessels, have not yet been reported as present in 
domesticated animals in the United States. The eggs of these flukes 
are usually much elongated. In the bovine blood fluke, Schistosoma 
bovis, the eggs (Fig. 32) are 160 to 180 microns long by 40 to 50 
microns wide, with a pronounced swelling in the middle and armed 
Fig. 34. Gaigeria pachyscelis. Eggs. Enlarged. From Gaiger, 1911. 
with a pointed spine at each end. In the case of this species, the eggs 
may pass in the manure and in the urine, as the veins both of the 
rectum and of the bladder may be inhabited by the flukes. 
Ruminants are infested by a large number of species of nematodes, 
some of which occur in the digestive tract or respiratory tract with 
the evidence of their presence in the form of eggs and larvae in the 
feces, and some of which occur in the blood, body cavity and various 
tissues and which cannot be determined as present by fecal examina¬ 
tions. 
37 
