Intestinal Parasites in Sheep and Goat. 285 



ated as it often is with the destructive strongyli of the lungs and 

 stomach, it largely contributes to the verminous epizootics and en- 

 zootics which are so common in sheep. 



Preve7ition and treatment will be the same as for strongylus con- 

 tortus. 



Strongylus Ventricosus. Curtice found this to be common 

 in the small intestine of sheep in autumn and winter. (See 

 " Worms of the Ox.") 



CEsophagostoma Venulosum {venula a small vein) . Mouth 

 circular, bounded by a prominent ring with six papillae. The 

 neck shows an ovoid enlargement followed by two lateral, narrow 

 alae. Male, 15 mm. long, with broad, trilobate, caudal bursa. 

 Female, 2^ mm. long. Vulva in front of the anus. 



Habitat. Intestine of goat, sheep and roe deer. Rare. 



CEsophagostoma Columbianum. Body narrowed at both 

 ends. Head bent to one side. Mouth terminal, large, round, 

 with six papillae and a chitinous ring, and two rows of teeth, 

 twenty-four in each, and the outer row the larger. CEsophagus 

 triangular. Neck has a ventral fold and extending back from 

 this for one-fourth the length of the body are two lateral alae. 

 Male, 12 ram. to 15 mm. long, with two spiculae and a broad hemi- 

 spherical bilobate pouch. Female, 14 to 18 mm. long; thicker 

 than the male ; tail acute ; anus midway between the vulva and 

 the tail. Ova elliptical 0.09 mm. long. 



Habitat. Cooper Curtice discovered this para.site in 1888 in the 

 nodules on the intestines of sheep at Washington, D. C, and later 

 free in the intestines. It is very common in American sheep, 

 north as well as south, the presence of the nodules being the rule 

 rather than the exception in sheep killed in New York. Its his- 

 tory is unknown from the passage of the egg with the faeces to 

 the entry of the embryo with food or water and its encysting it- 

 self in the walls of the intestines. From the cyst, however, it 

 escapes into the intestine, reproduces its kind and dies. It is 

 especially common in the caecum and colon during autumn and 

 winter, but it may invade any part of the small intestine. It 

 moults three times, once before it acquires mouth and digestive 

 organs, once after such acquisition, and once in becoming devel- 

 oped into the mature form. 



Pathogenesis. The embryos are first found encysted in pin- 

 head-like submucous nodules ; in larger nodules the encysted 



