130 BOARD OF AGRICULTURE. 



vaded, and those that are once attacked seldom or never re- 

 cover. The same remarks, concerning the means of preven- 

 tion, made under the preceding species, will apply equally to 

 this. If neglected, these parasites increase with great 

 rapidity, and thus the disease that they cause appears like an 

 epidemic, in certain localities destroying hundreds or thou- 

 sands of animals, while adjacent farms may be entirely free 

 from it. 



The Strongylus of the Hog (Strongylus parodoxus Mehlis). 



This is a slender, whitish or brownish worm, with a small, 

 simple head. The mouth has three small papillae. The 

 oesophagus is long and muscular. The anus is situated some- 

 what in advance of the posterior end of the body at the sum- 

 mit of a small papilla. The male becomes half an inch or 

 more in length, and has the caudal bursa bilobed, each lobe 

 with five rays, the lateral ones divided. The female grows to 

 the length of about an inch and a half, but is usually about 

 an inch long ; the tail is terminated by a point, turned to one 

 side ; the genital opening is near the posterior end and a little 

 prominent. This species is viAdparous. It inhabits the wind- 

 pipe, bronchial tubes, and lungs of swine. Its history and 

 the effects it produces are nearly the same as those of the 

 Strongylus filar ia. 



The Strongylus of the Intestine of the Hog (Strongylus 

 dentatus Rud.). 



This is a slender filiform species, about half an inch long, 

 which lives in the small intestine, coecum, and colon of hogs. 

 The head is obtuse and surrounded by six acute papillae. The 

 oesophagus is short and thick, muscular. In the male the 

 tail is truncated and provided with an oblique bursa, formed 

 of a single piece, strengthened by three subdivided rays ; 

 there are two slender spicules. The tail of the female is 

 elongated and slender, ending in a fine point ; the genital 

 opening is near the posterior end. 



The effects of this species and its history are little known. 



