Biological studies were conducted on a histozoic myxosporidan
Myxobolus insidiosus (Wyatt and Pratt, 1963) from the musculature of
Oncorhynchus tshawytscha (Walbaum). This organism is known to
occur in spring chinook salmon in Oregon and coho salmon O. kisutch
(Walbaum) in Washington. In addition Myxobolus kisutchi (Yasutake
and Wood, 1957) was...
This report summarizes the results of a field study of a population
of the Pacific mountain beaver, Aplodontia rufa pacifica, from
August 1965 through August 1967. The study site consisted of a 13. 5-
acre grid on a logged over area in the Coast Range Mountains of
Benton County, Oregon....
Organismal tolerance to abiotic environmental stresses contributes significantly to setting the distribution limits of organisms, as demonstrated by vertical zonation patterns in the marine intertidal zone. In this thesis, the ultimate (evolutionary) and proximate (mechanistic) causes of tolerance to temperature and emersion stresses associated with the intertidal zone were examined...
Using techniques that permit the direct observation of
fetuses in vivo, prenatal behavioral development was
compared among four species in the rodent family Muridae:
the Norway rat (Rattus norvegicus), Mongolian gerbil
(Meriones unguiculatus), cotton rat (Sigmodon hispidus), and
spiny mouse (Acomys cahirinus). Rattus and Meriones bear
altricial offspring, as do...
The karyotypes of five species of ranid frogs were determined
from metaphase plates of bone marrow cells. The colchicine, hypotonic-
citrate, blaze-dry technique was used to obtain the plates.
Morphometric datawere obtained from the karyotypes and compared
with other species of the genus Rana.
Like most other members of the...
Analyses of sympatric and allopatric populations of Sceloporus
occidentalis and S. graciosus from central Oregon indicate a high degree
of similarity in diet. Relative abundance, the equivalent number of
equally common taxa (E), and the probability of similarity (SIMI) were
used in the analyses. Shifts in diet between populations of...