The present state of knowledge permits only the grossest assessment of nutritional physiology of living brachiopods since most of the knowledge available on brachiopods is not addressed from this aspect and when it is, much of the information is derived from studies made without the use of modern investigative methods. Additionally, of the few studies that have been made on the physiology of the brachiopod digestive system, most have been on the genus Lingula. Unfortunately, this is one of only 2 genera that occupy an infaunal habitat, all other living genera are epifaunal forms (Table 1). The geographic distribution, habitat preference, and digestive modifications suggest that there are some differences in dietary characteristics between the infaunal and epifaunal brachiopods. With these limitations in mind, studies on physiology of digestive systems in other phyla will be used for comparison.