94 



in diflferent postmortem observations, it has been identified in sheep 

 from Utah. Cok)rado, and Nebraska. Mr. Codweis, of Granger, Colo., 

 a former slieep-owner in New Mexico, says that be has seen them there. 

 Mr. Samuel (Jollins, of Colorado Springs, Colo., who has slaughtered 

 sheep from Californiii, Oregon, Utah, Nebraska, and Colorado, says 

 that all sheep irom these States have them. Dr. Faville personally 

 told nie that he has seen them from Oregon sheep and from sheep in 

 New Mexico. Mr. Stewart's identification of Twiiia plicata from Mis- 

 souri sheep (National Live Stock Journal, Sei)tember, 1875) leads me 

 to suspect its presence in that State. When to these evidences of 

 wide-spread distribution we add those offered by the intermingling of 

 Western sheep by parentage and traCtic, and by the opportunities for 

 infection presented by the nearly unrestricted communication of the 

 ranges, we may believe that this distribution is necessarily wide- 

 spread. Its distribution at present is from Oregon and Wyoming south- 

 ward and from Nebraska and Missouri westward, or, more accurately, 

 from the ninety-fifth degree of west longitude westward and from the 

 forty-fifth degree nortli latitude southward. It coincides with the dis- 

 tribution of the sheep in, those parts, and more especially with that of 

 the descendants of the Mexican or Spanish sheep with which nearly all 

 of the larger ranches were originally stocked. The precise limit of its 

 Eastern distribution is unknown, but is probably limited to those por- 

 tions of Nebraska, Kansas, and Missouri to which Colorado feeders have 

 been sent prior to selling them to the Chicago markets. 



There are at present no facts at hand to show that the parasite exists 

 east of the Mississippi Eiver. In two instances a number were found 

 in sheep slaughtered in Washington, D. C, but these animals were said 

 to have come from Chicago, 111. 



Life history, — All of the life history of this tcviiia that is at present 

 known has been learned from post-mortem dissections and microscopic 

 investigation. 



The adults were found in yearlings and older sheep throughout the 

 year. No adults have yet been found in lambs less than ten months 

 old. The smallest stages of the immature twnia may be found in all 

 young sheep over ten months old. They are usually most abundant 

 in lambs, yearlings, and two-year olds. Although a sheep may be in- 

 fected with a number of t(V)iifV of about the same size, indicating an 

 infection covering but little space of time, it is more usual to find the 

 parasites of various sizes, indicating a continuous infection. The re- 

 tention of food and liquids for some little time in the rumen and reti- 

 culum may account for this in part. These varying sizes continue 

 from May until December. Sheep examined in Mny presented various 

 sizes and indicated infection in former months. No other data showing 

 infection during winter months were obtained. The smallest tccnice 

 are found in the duodenum ; those found in the gall ducts are larger. 

 Twnia less than 2""" long have been found in the duodenum after the 



