Righting behavior was examined in the asteroids Henricia
leviuscula and Leptasterias aequalis by repeating a standard laboratory
righting trial with a large number of individuals of each species,
and analyzing the observations made by statistical methods. Detailed
observations on the righting method, including leading pairs of
arms and righting time...
Rhabdocoels of the genus Paravortex are parasites of marine
molluscs. The bent-nosed clams, Macoma nasuta(Conrad, 1837) of
Yaquina Bay, Lincoln County, Oregon are commonly infected with a new
species of Paravortex. The morphology of the adult worm has been
described and it has been compared to the other three species...
The pea crab Fabia subquadrata is frequently found as a symbiont
of mussels, living within the mantle cavity. This study examined
the nature of this symbiotic relationship by recording the pattern
of distribution of individuals in a mussel bed, testing responsiveness
to host secretions, and observing the feeding mechanics and...
Morphological changes which occur during tentacle formation
have been described in the colonial athecate hydroid Cordylophora
lacustris. These changes involve an outpocketing of mesoglea into
a finger-like extension of the hydranth. Gastrodermal cells line the
inside of this extension of mesoglea while ectodermal cells cover the
outside. Electron micrographs reveal...
Osmotic and ionic regulation was studied in the North
American crayfish Pacifastacus leniusculus (Dana), stepwise acclimated
to increasing salinities. Stepwise acclimation involved transferring
crayfish at 48 hour intervals from freshwater to 100% seawater
in 20% increments. In experiments where 70% seawater was
used, animals were moved directly from 40 to...
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...
Metabolic rate-temperature responses of three related
species of sea urchins were determined using oxygen consumption
rate measurements. The three species used were Strongylocentrotus
purpuratus, Strongylocentrotus franciscanus, and Allocentrotus
fragilis. All measurements were made using an oxygen
macro-electrode, physiological gas analyzer, and sealed respiratory
container. Two series of experiments--field-acclimatized and
temperature-acclimated--were...
The syllid polychaete Autolytus varius reproduces in the spring
and early summer in Yaquina Bay, Oregon, The fertilized female
epitokes, or Sacconereis, carry the developing eggs and larvae in a
ventral sac until the larvae are ready to be released; incubation
lasts 14 to 18 days in the laboratory, The...
The patterns of cell proliferation in the choroid plexuses of
embryonic and post-natal hamsters were studied by means of auto-radiography
(H³-thymidine). In addition, the PAS technique was
used to determine the times of first appearance, relative amounts,
location, and times of disappearance of glycogen free the plexuses.
Many mitotic figures...