It is the purpose of this study to make gross and histological comparisons of the various segments of the intestinal tracts of the jack rabbit and the pika. The two animals used for this study were the desert jack rabbit (Lepus Californicus deserticola Mearns), and the pika (Ochotona princepts uinta Hollister). The jack rabbits were found only in the desert valleys and low foothills in the areas studied. These areas are typically open bush or sage brush types of communities. The pikas were restricted to certain high rockslides in this region. These areas are described more completely in the section on Methods and Materials. This study is limited to a comparison of the gross and microscopic anatomy of the idgestive tube in these two animals.