strata is the apparent reduced resident rodent populations in the vicinity of GZ. Figure 1 presents a diagram of the inner trapping grid in Area 11-C in which isopleths mark the approximate boundaries of activity strata defined by Gilbert et al. (1975). Trapping stations are 50 feet apart. The inner grid with a width of 350 feet and a length of 1200 feet was trapped most frequently. The area encompassed by the High Activity Stratum (>25,000 CPM 24lam) represents approximately 24% of the inner grid and is indicated by a solid-lined isopleth. Table 4 presents data on total number of captures and number of resident rodents encountered in the High and Low Activity strata of the inner grid during 18 months of study in Area 11-C. If we assume random distribution of animals in the grid, an assumption which is probably met only under ideal conditions, an estimate of the number of animals captured in the High Activity Stratum can be made by multiplying the total number of captures (447) by the proportion of the area encompassed by the High Activity Stratum (23.5%). One hundred and five captures are expected using these calculations, which is not significantly different than the number actually captured in this stratum (103). All species shown in Table 4 were captured in both High and Low Activity strata. The number of resident animals expected in the High Activity Stratum can be estimated in the same manner. There were 82 resident animals in the Only nine grid, of which 19 were expected from the High Activity Stratum. resident animals, however, were recorded from this stratum, a significantly Of the six resident species, only four (P<.01) lower number than expected. In addition, of these resident were found in the High Activity Stratum. animals, only one species (D. merriami) was represented by more than two individuals. These data show a reduced species richness, species diversity (H'), and population density of resident rodents in the High Activity Stratum near GZ and illustrate the problems of collecting adequate samples of most species of rodents. We do not now have an explanation for the reduced number of residents in the High Activity Stratum. Beatley (1976) reported that D. merriamt replaced D. mterops as a dominant rodent in some disturbed areas of NTS. Whereas the low number of D. mtcrops may be explained by habitat alteration around GZ, it does not explain the absence of resident A. leuweurus or O. torrtdus. Whereas a reduced number of some species of rodents may be expected when native habitat is altered, experience by the investigators in the Mohave desert suggests that many rodents, particularly A. leucurus, are likely to be more numerous in disturbed habitats with sufficient vegetative cover. We do not believe, therefore, that the depauperate rodent fauna of Area 11-C, GZ, can be explained satisfactorily strictly on the basis of mechanical disturbance, as the area is not denuded of vegetation. We are not suggesting at this time that this phenomenon is related directly to Pu or Am levels; however, it is a hypothesis worthy of further investigation. Hematologic Studies Tables 5 and 6 present comparative hematologic values of three species of heteromyid rodents from Area 11-C, NTS, and a control site in the Charleston Mountains of southern Nevada. Whereas substantial variation is’seen in Table 5 for most of the hematologic characteristics due partially to small sample size, the two populations, in general, compare favorably with three notable 205