Evolutionary inferences made on the basis of cytogenetic data are of considerable value to biologists and anthropologists. Although a considerable amount of data has accumulated on the rates of cytogenetic change among lineages, there has been a general failure to appreciate the implications of these observations for the overall study of the evolutionary processes, and for the interpretation of other bodies of cytogenetic data. My goals in this paper are to discuss evolutionary rates; to focus on the factors influencing the rate of karyotypic change; and to show how phylogenetic influences may be made from karyotype data -- with special reference to the order Primates.

The primary purpose of this paper is to describe the lithic collection from the chultun in such a way as to provide information for interested lithic analysts and to make comparison with other collections possible. However, context can be an important element of description, and our understanding of context can influence conclusions drawn from the characteristics of the collection, In the examination of the chultun collection, therefore, each item or class of items is interpreted with a view to suggesting an explanation for its incorporation into the refuse. In general, the following alternative possibilities have been considered: 1) the item class consists of an unwanted byproduct of manufacture or resharpening; 2) the item was exhausted; 3) the item was broken, a) during use, or b) during manufacture; 2+) the item was abandoned unfinished. For some lithic items none of these possibilities seems very probable while for others several seem equally probable. Finally, the consequences and implications of the prehistoric selection of these items as refuse will be considered.