Intestinal Parasites in Sheep and Goat. 287 



Habitat. Small intestine of sheep and goat, most commonly 

 with heads buried in the mucosa, sucking blood. Sometimes in 

 large intestine. Stiles reports the worm as prevailing in sheep in 

 the Gulf Coast States, along with the Strongylus Ostertagi. In 

 keeping with the common experience with other species of the 

 bloodthirsty Uncinaria, he found it extremely injurious "doing 

 more harm than all the other parasites of the sheep." 



Lif e- History . Though the life-history of the U. Cernua has 

 not been especially investigated, there can be no doubt that it fol- 

 lows the general rule of the genus uncinaria. 



The ova, laid in the intestine, usually undergo segmentation in 

 the ingesta but are expelled in this condition in the faeces. Young 

 worms direct from the egg never reach maturity without leaving 

 the intestine. 



The rhabditiform embryo escapes from the egg after 15 days, 

 hatching in the manure or in a warm moist environment though 

 development may be arrested for months in cold weather. The 

 egg is destroyed in too much water or by frost. The embryo 

 shows the common embryonic oesophagus of the strongyli : first, 

 an elongated large section, followed by, second, a narrow, thin 

 middle portion ; and third a dilated oval or globular bulb armed 

 with triradiate chitinous projections. This last has the appear- 

 ance of a triturating cavity or gizzard. 



The embryo lives in water or moist earth, and before reaching 

 maturity it passes through four successive moultings. The buccal 

 end is thick and blunt, the tail long and finely pointed. There is 

 a distinct digestive apparatus ending in anus 50 /* in front of the 

 tail. On the second or third day it makes its first moulting and 

 on about the fifth day its second having attained a length of 480 ij. 

 by 30 /*. The chitinous lining of the buccal cavity and oesopha- 

 gean bulb disappear, through the skin can be seen three lips each 

 bearing two papillae, the tail is shorter and blunter, and the body 

 contracts and loosens from its outer skin ( ' ' encystation " ) , pre- 

 paratory to the third moulting. The young uncinaria is now 

 prepared to invade the intestine and if taken' in by the sheep or 

 goat, it advances toward maturity; otherwise it perishes in no 

 great length of time. Looss, however, has succeeded in keeping 

 them alive at this stage for thirty days in water. He also sup- 

 po-ses that they can be dried up and carried on dust without loos- 



