The opossums having home ranges entirely within the study area were those most likely to be caught repeatedly and at different locations, while those with ranges centering near the edge of the area, or outside of it tended to be caught at fewer locations and less frequently. For those animals with ranges partly outside the study area, the captures recorded would represent only one sector of the home range and would tend to be near together, so that many of the radii computed for individual home ranges are too small. Each average figure for home range is perhaps erroneously low for this reason. The error tends to be greatest for those taken at only two locations, and least for those trapped at the greatest number of different locations. Approximate size of the usual home range is apparent from the several figures although various unknown or unmeasurable factors distort the data. The usual home range of the opossum in the area of the study is in the neighborhood of 50 acres or a little less. With the data available no significant differences in sizes of home ranges are discernible between males and females nor between adults and young of the year. Shifts occur frequently, contributing to population turnover, which may result in almost complete replacement of individuals in the course of a year's time, on an area of less than a square mile. DISPERSAL OF YOUNG One hundred and fifteen small young of 14 different litters were marked while still attached to the mother's teats in the pouches. A fairly high rate of mortality probably is normal in the small dependent young and further mortality probably resulted from the deleterious effects of examining and handling them and the females that carried them. At any rate, 47 of 208 young recorded, were missing at subsequent recaptures of the females, before the young were old enough to become independent. It is almost certain that the actual losses were much higher, because the records for each female cover only part of the period during which young are carried in the pouch. Fifteen of these marked young of seven different litters were recaptured after periods of months, when they were well grown or adult and the locations of these recaptures afford information concerning the animals' dispersal. Their records are summarized below. Opossums that wandered much more than half a mile or at most three-fourths of a mile from the place of original capture were unlikely to be recaptured, and some originally recorded at sites near the edge of the study area might have moved beyond its boundary with much shorter shifts. Date of capture and Date of Distance Sex marking as pouch young recapture in feet