ABSTRACT
In a recent discussion of the distribution of earthworms in North America, Reynolds (1994a) discussed the three steps of biogeographical theory. The first step is descriptive or fciunistics, the gathering of facts and enumeration of animals in an area, including research and literature surveys. This step, al though seldom achieved, seeks to present a clear distributional picture of all the animals in all areas. The second step is the classification o f data, or grouping of the distributional data according to as many different points of view as a particu lar investigation may find necessary, including a comparison of distributional ranges of phylogenetically related groups. This step also analyzes the fauna of a geographically, ecologically, or historically uniform area. The third and final step, causal analysis, tries to explain the reason for the present distribution as it has been presented. It is from this step that the principles of biogeography emerge. At present, in North America, we are probably somewhat between the first two stages with megadriles (Reynolds 1975a, 1976a, 1994a).
