94 



in different postmortem observations, it has been identified in sheep 

 from Utah, Colorado, and Nebraska. Mr. Codweis, of Granger, Colo., 

 a former sheep-owner in New Mexico, says that he has seen them there. 

 Mr. Samuel Collins, of Colorado Springs, Colo., wbo has slaughtered 

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

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

 told me that he has seen them from Oregon sheep and from sheep iu 

 New Mexico. Mr. Stewart's identification of Twnia pUcata from Mis- 

 souri sheep (National Live Stock Journal, Sei)tember, 1S75) leads me 

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

 widespread distribution we add those offered by the intermingling of 

 Western sheep by parentage and traffic, 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, moie accurately, 

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

 forty-fifth degree north 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 probablj' limited to those por- 

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

 been sent jjrior 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 lliver. In two instances a number were found 

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

 to have come from Chicago, 111. 



Life history. — All of the life history of this tcenia 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 tcenia may be found in all 

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

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

 fected with a number of twnim 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 iii part. These varying sizes continue 

 from May until December. Sheep examined in May presented various 

 sizes and indicated infectiou iu former months. No other data showing 

 infection during winter months were obtained. The smallest twnim 

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

 Tmnia less than 2™'" long have been found in the duodenum after the 



