The Weberian mechanisms of three Utah Lake suckers (Catostomidae: Catostominae; Catostomini), Catostomus fecundus Cope and Yarrow, Chasmistes liorus Jordan, and Catostomus ardens Jordan and Gilbert, were examined, described, and compared, and a statistical analysis was made of some of their more important differences. The mechanisms were found to be basically similar to one another and to those of other Catostomini as previously described and/or illustrated. They are individually distinct, but each varies within its own limits, the intraspecific variation being greatest in the wider-ranging Catostomus ardens and least in the seemingly most restricted Catostomus fecundus. From the evidence at hand it appears that the above taxa are three distinct species. Chasmistes liorus is more abundant that Catostomus fecundus; Catostomus ardens presumably is very rare. Catostomus fecundus seems more closely related to Chasmistes liorus, and future studies may verify that Catostomus fecundus should be transferred to the genus Chasmistes.

This paper reports the incidence and associations of four species of mites, Paraneonyssus icteridius, Ptilonyssus n. sp. "A", Sternostoma n. sp. "A" , and Speleognathus sp., found in the nasal cavities of the common red-wing blackbird (Agelaius phoeniceus ssp.) and Brewer's blackbird (Euphagus cyanocephalus cyanocephalus Wagler) over-wintering in the vicinity of Provo, Utah County, Utah. Three species of mites are reported for the first time from these birds, and two of these three are undescribed species.

Population and community studies dealing with radiation stress have essentially neglected the mites. When references have been made to the responses of mite populations to ionizing radiation, the form of radiation has almost always been gamma. This study reports results of naturally occurring populations of desert mites, at the Nevada Test Site, to ionizing radiation--largely beta. Eighteen species groups were identified from Berlese samples and tested for stress responses with species diversity indices and analyses of variations in predator-prey ratios. General agreement with previous studies showed a decreasing pattern in these two tests within the controls. This was interpreted as the normal seasonal pattern. The increase of these measurements, within the irradiated sites, was due to large fluctuations in the numbers of a few species groups.

A comparative morphological study of Bryobia rubrioculus {Scheuten} from 24 worldwide sites was made to determine if enough significant variation existed to designate the mites from each locale as an isolated population. Forty-seven characters were then selected and measured for each mite and analyzed with Ward's error sum cluster analysis procedures. These analyses led to the conclusion that: {1} B. rubrioculus tends to form distinct populations within each respective locale, and mites from locales that did not form clusters are possibly a result of automictic parthenogenesis and introductions from other areas; {2} B. rubrioculus is distinctly separate from Bryobia praetiosa {Koch} and not part of a large "praetiosa" complex; {3} mites from the U.S.S.R. are not Bryobia redikorzevi Reck, but, instead, are B. rubrioculus; and {4} some of the characters used in earlier classifications of B. rubrioculus are excellent.

A systematic study of parasitic mites on kangaroo rats at the Nevada Test Site, Nye County, Nevada, was conducted from August, 1959, to December, 1961. The intent was to determine their kinds, numbers, seasonal occurrence, and ecological relationship with Dipodomys merriami merriami Mearns and Dipodomys microps occidentalis Hall and Dale in nuclear disturbed and contiguous undisturbed areas. Study areas were established in three major valleys -- Jackass Flats, Yucca Flat, and F renchman Flat.

A review of the literature shows that extensive work has been done on the morphology and histology of the adrenal gland of the domesticated rabbit, but it appears that little or no work has been done on other members of the order Lagomorpha. Approximately one hundred specimens of rabbits of various ages and sizes, and of both sexes, were collected over a period of nine months. All adrenal glands were fixed by immersion and were embedded in paraffin. The majority or the glands were sectioned at eight or twelve miora, and were stained with Mallory's triple stain. This investigation shows that the gross morphological variations of the adrenal gland of' each species of native rabbits examined is almost as extensive as the variation found within the different genera and families of the order Lagomorpha. There are fewer histological Variations within a given species, but more extensive variations within genera and families of this order. It must be emphasized that not all morphological and histological structures found in the adrenal gland of all rabbits are the same. What may appear to be a typical histological structure or arrangement in one species of rabbit is not necessarily the typical structure or arrangement in all species.

This paper deals with the life history and distribution of the Spurred Towhee (Pipilo erythropthalmus moutanus Swarth). Research was begun in April, 1955, and terminted in June, 1956. The preferred habitat of this bird is the mountain slopes, canyons. and streamsides covered with a shrubby type of vegetation, usually between 5,000 and 8,000 feet in elevation. Distribution of the Spurred Towhee is throughout the central Rocky Mountain region in the states of Wyoming, Utah, Colorado, Arizona, western half of New Mexico, and into northern Mexico. During the winter these birds are found concentrated in the lower valleys along the streams in some areas and in the lower reaches of the foothills in others. In April the flocks disband and the birds pair and establish territories. There are three distinct songs or sounds made by the towhee, and two of these have been analyzed in detail by first tape recording them and then analyzing them on a sona-graph. Few data were assembled concerning territorialism, but it is thought to exist. The five nests found during this study were all robbed of either their eggs or young. They were constructed upon the ground, with an inner lining of dry grass and an outer shell of sagebrush bark or cedar bark. The four nests found in Utah County were all under sagebrush. The usual clutch size is four. The female does all the incubating and the male sings vigorously during this time. The growth rate of the young is rapid. Only the male feeds the young, at least during the first six days of nest life, while the female does all the brooding. June 9 was the earliest juvenile towhee, were observed out of the nest. The principal source of food, according to another worker, is insects, except during winter months. The ideal habitat where populatlons were found to be highest was in areas where the vegetation was clumped with intermittent open spaces. Size, density, and kind of cover seemed to be the most important factors affecting populations, while slope and exposure had only an indirect effect.

A field study was made to correlate cattle grazing patterns of steep terrain with the rest-rotation grazing system. Line-plot transects were positioned across each of three heavily grazed, steep canyons. The rest-rotation system as practiced on the Gooding Cattle Allotment is resulting in good forage use as the animals are grazing forage on slopes up to 60%. Level contour trails extending across slope faces made it possible for cattle to graze on steep slopes at distances up to 80 chains from water. Contour trails originate at watering loctions; hence better distribution of water could be expected to result in better distribution of cattle on steep ranges. Downed timber blocked some contour trails and its removal could inrease forage utilization. Salt should not be placed along a contour but upslope or downslope to increase cattle distribution.

Plankton samples were taken periodically from one station in Salem Lake from the fall of 1955 through the winter of 1957. Other data including the pH, dissolved oxygen content, turbidity, brightness of day, temperature, and time of day were recorded at the time of each collection. The plankton samples were centrifuged and preserved in a 4% formalin solution. They were later examined microscopically, and density, percent density, and percent frequency calculations were made from them for ten selected species and for the five phyla which they represent.

No description available.