bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ventilatory Muscle Activity in Intact Preparations of Aeshnid Dragonfly Larvae
Authors: Pickard R. S. , Mill P. J. 
Published: April 2021

ABSTRACT
The expiratory role of the segmental, respiratory dorso-ventral muscles, and the inspiratory role of the subintestinal muscle, have been confirmed using intact preparations of aeshnid dragonfly larvae. The strain developed by individual respiratory dorso-ventral muscles has been measured. The respiratory dorso-ventral muscles all cease firing simultaneously, about 100 msec before the sterna are fully raised, and do not have any mechanical effect on the sterna after this time. It is suggested that the delay is caused either because the role of these muscles is to lift the sterna past some critical position, and/or because of the inertia of the expiratory current. Periodically the sterna are raised and then lowered slowly in a series of steps, each pause in the lowering coinciding with activity in the respiratory dorso-ventral muscles. This form of ventilation is compared with others previously described. In normal ventilation, and in other types of ventilation, activity in the respiratory dorso-ventral muscles shows a pronounced tendency to begin in the most posterior segments and to continue for longer periods in those segments. Some aspects of the central neural connexions involved in normal ventilation are discussed.
Anal Valve movement and Normal Ventilation in Aeshnid Dragonfly Larvae
Authors: Mill P. J. , Pickard R. S. 
Published: April 2021

ABSTRACT
Anal valve movement and abdominal sternal movement were photographed with a ciné camera during normal ventilation to obtain a correlation between the two parameters. As the sterna are raised (expiration) the anal valve opens to about one third of its maximum. At peak sternal movement the anal valve opens fully and these events mark the transition between expiration and inspiration. The anal valve finally closes towards the end of inspiration. The narrow aperture of the anal valve during expiration, coupled with the increase in pressure in the branchial chamber, causes the expired water to be forced well clear of the anus. Conversely, the wide aperture during inspiration and the small negative pressure in the branchial chamber ensure that water is drawn in from close to the animal, and so there is minimal mixing of expired water with inspired. The relationships between water flow, anal valve movement, branchial chamber pressure, sternal movement, pleural strain, and activity in certain expiratory and inspiratory muscles are discussed.
The Movement of Glucose and Glycine Through the Tissues of Corymorpha Palma Torrey (Coelenterata, Hydrozoa)
Authors: Chapman G. , Pardy R. L. 
Published: April 2021

ABSTRACT
The rate of diffusion of 14C-labelled glucose and glycine across isolated mesogloea and across the mesogloea and cell layers of the large solitary hydroid, Corymorpha was measured. Diffusion coefficients of glucose and glycine in mesogloea were found to be about 16 times lower than their values in water and of the same order as their values in dialysis tubing and Millipore filters,
Electrotonic Conduction in the Optic Nerves of Planorbid Snails
Authors: Patton Marion L. , Rater Stanley B. 
Published: April 2021

ABSTRACT
The conduction of information from the eyes of two basommatophoran snails has been investigated. In the optic nerves of HeHsoma trwolvis and Planorbis corneus a flash of light to the eye produces a procaine-insensitive DC potential that is graded with stimulus intensity and lasts as long as the stimulus. The similar spectral sensitivities, time courses and latencies of the ERG and the slow wave of the optic nerve suggest that the DC response is a decrementally conducted receptor potential. Superimposed on the DC shift are procaine-sensitive oscillations. The oscillations may be either local or propagated regenerative events.
Burst Activity of the Buccal Ganglion of Aplysia Depilans
Authors: Rose R. M. 
Published: April 2021

ABSTRACT
The activity of the buccal ganglion of Aplysia depilans is manifested as regular and sequential bursts of nerve impulses. Regularly firing bursts are seen in the absence of feeding movements. Sequences of bursts lasting for several minutes have been recorded during feeding movements induced by a natural stimulus. A feed-back system has been used to produce bursts in certain other cells synchronous with the regularly firing units. During sequences of bursts there is an alternation of activity between the two groups of neurones. One group is made up of four cells discharging synchronously but within different ranges of frequency. A mathematical model of this activity will be presented in another paper.
The Penetration of Some Non-Polar Molecules in Solution Through the Egg-Shells of Locusta Migratoria Migratorioides and Teleogryllus Commodus
Authors: Browning T. O. 
Published: April 2021

ABSTRACT
The micropylar ends of eggs of Locusta migratoria migratoria were cut off, the tissues were removed, and the empty egg-shells were filled with water or with a solution. The open end was tied off to form a balloon. Balloons containing water were placed in a solution, and those containing solution were placed in water. Balloons containing glucose solution swelled in water and those placed in glucose solution shrank. Little change was observed either in balloons containing urea or in those placed in urea. Results with solutions of malonamide were erratic. Empty egg-shells of Teleogryllus commodus were perfused with radioactive solutions of substances of varying hydrated molecular radii. The smaller molecules (acetamide and urea) passed through the shell into the surrounding liquid more rapidly than the larger ones (glucose and ribose). Shells in which the serosal cuticle was absent were more permeable than those in which it was present. Molecules penetrated living eggs much less readily than they passed out through dead egg-shells. The results are discussed in relation to the permeability of the shells of insect eggs to water and their capacity to restrict the leaching of molecules from the tissues of the egg.
Tissue Culture and Its Contribution to Biology and Medicine
Authors: Fell H. B. 
Published: April 2021

ABSTRACT
I feel deeply honoured at being invited to give the George Bidder Lecture this year. I was asked to talk about tissue culture ; as it happens this is a not inappropriate subject for the present occasion, because Dr Bidder was one of the original benefactors of the Cambridge Research Hospital, which later was renamed the Strangeways Research Laboratory in honour of its founder and became the chief centre for tissue culture in this country. When the Hospital was built in 1911, Dr Bidder thought that it ought to have more land and so with characteristic generosity provided the necessary funds for the purchase of another acre. I cannot tell you how grateful we have been for that extra land as the Laboratory has developed and expanded through the years, and how much we appreciate Dr Bidder’s foresight and kindness.
Input Sources and Properties of Positionsensitive Oculomotor Fibres in the Rock Lobster, Panulirus Interruptus (Randall)
Authors: York B. , Yanagisawa K. , Wiersma C. A. G. 
Published: April 2021

ABSTRACT
Sets of head-up, head-down, eye-up and eye-down motor fibres were studied in the oculomotor nerve of the rock lobster. An eye-withdrawal fibre was also investigated. Apart from the statocyst input, light distribution on the eyes has the strongest influence on the position-sensitive fibres. Weaker optokinetic input from moving targets is also present. Strongly habituating input is obtained from the antennal joints. This input causes orientation of the eye toward the direction in which the antenna points. The same antennule movement in the vertical plane can result in either excitation or inhibition of the head-down fibre, suggesting the presence of two opposing inputs, presumably from the statocysts and basal joint receptors of the antennule. The inputs on to the position-sensitive fibres which indicate body position are such as to stabilize the eye position in space during body movement. The optokinetic and antennal joint inputs are probably involved in tracking and antennal pointing reactions. The eye-withdrawal fibre is stimulated by touch of the head and around the eye, but is inhibited by the excited state.
Eco-Physiological Studies of An Intertidal Crustacean, Pollicipes Polymerus (Cirripedia, Lepadomorpha)
Authors: Fyhn H. J. , Petersen J. A. , Johansen K. 
Published: April 2021

ABSTRACT
Physiological responses to environmental stresses of the intertidal cirriped Pollicipes polymerus have been studied by combined field and laboratory experiments. The body temperature of air-exposed animals is always lower than expected from the heat load. Evaporation from the peduncle is responsible for the heat loss. The rate of water loss by evaporation from the peduncle cuticle is 1·5 μ l/cm2 h mmHg both at 21 and 27°C. The transpiration is proportional to the saturation deficit of the air. The water loss from the capitulum is negligible in comparison to that from the peduncle. The haemolymph osmolality of animals in the field increases during exposure to sunshine and decreases during exposure to rain. The increase in haemolymph osmolality during desiccation is equal to that calculated from the decrease in body water. The water loss during air exposure is adequately replaced during submersion, probably by osmosis. Pollicipes is an osmoconformer but is 5–20 m-osmoles hyperosmotic. It tolerates sea-water dilutions down to about 50 %. The hyperosmolality seems to be balanced by a high internal hydrostatic pressure. An excretory activity is observed. The excretion is isosmotic to the haemolymph and is possibly an ultrafiltrate of the latter. The muscle cells show volume regulation, but free amino acids seem to be unimportant in regulation of intracellular osmolality. The concentration of ninhydrinpositive substances in the muscle tissue is about 200 mm for animals in full strength sea water.
Specific Re-Innervation of Limbs Transplanted Between Segments in the Cockroach, Periplaneta Americana
Authors: Young D. 
Published: April 2021

ABSTRACT
The connexions of single, identified motor neurons have been studied in the thoracic ganglia of the cockroach, Periplaneta americana. Selected cell bodies were identified on purely morphological criteria from one animal to another. Similarly, serially homologous cell bodies were identified from one ganglion to another. Their connexions to particular limb muscles were demonstrated by intracellular stimulation through the cell body and subsequent marking with procion yellow dye. Serially homologous cell bodies in the mesothoracic and metathoracic ganglia innervate serially homologous muscles in the mesothoracic and metathoracic limbs. Metathoracic limbs transplanted to the mesothoracic segment retain their metathoracic characteristics. They become functionally incorporated in the mesothoracic segment and are used normally during walking movements. These transplanted metathoracic limbs become re-innervated from the mesothoracic ganglion. Identified mesothoracic cell bodies make specific connexions with those metathoracic muscles which are the serial homologues of their own muscles.
Light-on Effects and the Question of Bimodality in the Circadian Flight Activity of the Mosquito Anopheles Gambiae
Authors: JONES M. D. R. , CUBBIN C. M. , MARSH D. 
Published: April 2021

1. The pattern of non-specific flight activity in Anopheles gambiae females appears to be bimodal, with an initial peak followed by about 12 h of secondary activity, with a maximum 6-10 h after the main peak.
2. The secondary activity is more apparent when the activity level is high, and can account for over 60% of the total activity. When D &lt; 12 h activity is curtailed by the inhibitory effect of light, but there may be a minor peak in the light period, 8-9 h after light-off.
3. The main peak normally follows light-off, but is delayed in LD 3:21 and 1:23.
4. There may also be a peak at light-on if it is abrupt and occurs during the active half of the cycle. The peak is not observed if the light-intensity is changed slowly.
The Landing Response and Visual Processing in the Milkweed Bug, Oncopeltus Fasciatus
Authors: Coggshall John C. 
Published: April 2021

ABSTRACT
The landing response of the milkweed bug Oncopeltus fasciatus consists primarily of extension at one leg joint (femur-tibia) of each of the front four legs upon presentation of the appropriate visual stimulus. Small-field peripherally directed angular motion in the frontal visual hemisphere is sufficient to elicit the landing response. Movement from the periphery is not an effective stimulus. Response latency to a large-field peripherally moving striped pattern decreases monotonically with increasing angular velocity. This decrease is consistent with what is known of the dynamics of motion-detecting neurones in other insects. It is suggested that motor mechanisms controlling the landing response, opto-motor turning reactions and flight-power behaviour receive inputs from a common neural motion-detection system.
Spatial Organization of Respiratory Neurones in the Medulla of Tench and Goldfish
Authors: Waldron Ingrid 
Published: April 2021

ABSTRACT
A minimum of 2000 neurones in the medulla of the tench have cyclic activity that is phase-locked to the respiratory cycle. These respiratory neurones are not uniformly distributed throughout the medullary region where they occur. They tend to occur in two bilateral groups, each of which, toward its rostral end, tends to be split into a dorso-lateral and ventromedial group. Specific patterns of activity are more common in some regions than in others. No evidence was found for anatomically localized groups of neurones with interactions primarily within the group. Neurones within 0·2 mm of each other are more often either synchronous or anti-synchronous than are neurones separated by a distance of 0·5–1·0 mm, but so are neurones separated by 1·0–2·0 mm. Contrary to a speculation by Shelton, respiratory neurones are not bunched into anatomical clusters with a diameter of 0·6 mm or less.
Expansion and Contraction of the Oral Disc in the Sea Anemone Tealia Felina
Authors: Mcfarlane I. D. , Lawn I. D. 
Published: April 2021

ABSTRACT
Electrical stimulation of the SS 1 of Tealia felina causes inhibition of spontaneous activity and increase in length of oral disc radial muscle preparations. This response is elicited over a wide stimulus frequency range (1 every 2 sec to 1 every 30 sec). The response shows a slow onset and a long recovery period. Stimulation of the nerve net at frequencies between 1 shock every 5 sec and 1 shock every 20 sec produces slow contraction. The radials also show fast contractions to shocks less than 2 sec apart. Dissolved food substances excite the SS 1 in the column. The sensory response to application of food extract to a small area of the column shows evidence of sensory adaptation. These observations are related to the pre-feeding response of Tealia and a model for oral disc expansion is described.
Brightness Discrimination in Larvae of Plaice and Sole
Authors: Blaxter J. H. S. 
Published: April 2021

ABSTRACT
The brightness discrimination of larvae of plaice and sole was tested by subjecting them to a choice of moving phototactically to one of two horizontally opposed light sources.
At higher light levels, above 100– 10−1 m-candles, they moved to the brighter of the two lights; below 10−1– 10−2 m-candles they moved to the dimmer.
Brightness discrimination, expressed as the increment (ΔI) discriminated as a percentage of the dimmer light (I) (the Weber fraction), was of the order of 60– 200 %.
The Eye and Colour Change in the Minnow (Phoxinus Phoxinus L)
Authors: Gentle Michael J. 
Published: April 2021

ABSTRACT
Counts were made of the retinal receptors and observations were made of the colour of the minnow, Phoxinus phoxinus L., following the surgical removal of parts of the dorsal and ventral retina. It was found that there were greater numbers of retinal receptors in the temporal field than in the rostral field of the eye. There were very few triple and quadruple cones but a large number of double and single cones in the ventral retina compared to the dorsal. Surgical removal of the dorsal retina or only part of it resulted in the fish being fully dark-adapted on a black or white background. Surgical removal of the ventral retina resulted in the fish assuming an intermediate colour on a white background and a darker tint on a black background.
The Burst Activity of Different Cell Regions and Intercellular Co-Ordination in The Cardiac Ganglion of the Crab, Eriocheir Japonicus
Authors: Tazaki Kenro 
Published: April 2021

ABSTRACT
Various patterns of burst activity in the cardiac ganglion cells of the crab Eriocheir japonicus were observed by means of intracellular electrodes. The pacemaker for burst initiation is located among small cells, and it induces small synaptic potentials in the large cells, increasing their excitability. The anterior large cells generate slow potentials by synaptic activation. The slow potential is the spike generator. The anterior large cells are capable of initiating slow potentials in their own somata without synaptic activation from the small cell. Non-synaptic maintained depolarization takes place in the anterior large cell membrane. The after-depolarizations are cumulative and can develop the slow potential, leading to repetitive firing. The posterior large cell is innervated by two pre-synaptic nerve fibres, one being the small pacemaker cell and the other the anterior large cell, showing that it is a follower. Electrical interaction is present among ganglion cells. Positive feedback through electrical connexions is observed between large and small cells. The cardiac ganglion of the crab has some features common and similar to those found in the ganglia of both the lobster and Squilla.
Sound Discrimination by the Bicolor Damselfish, Eupomacentrus Partitus
Authors: Myrberg Arthur A. , Spires Juanita Y. 
Published: April 2021

ABSTRACT
Males of laboratory and field colonies of the bicolor damselfish, Eupomacentrus partitus, showed significantly greater response to playback of courtship sounds of conspecifics than to playback of structurally similar and fully analogous sounds of two closely related and sympatric congenerics, E. leucostictus and E. planifrons. Relative levels of responsiveness by these colonies differed, however, in that laboratory males showed a significant difference in courtship during playback periods of congeneric sounds (recorded in the laboratory) whereas field males showed no such difference. Field males, though responding well to typical laboratory sounds from conspecifics during tests which did not include playback of field sounds from conspecifics, failed to respond well when playback periods did include such field sounds. Present evidence demonstrates that male bicolors possess an excellent discriminative ability within the acoustic modality and that such discrimination is based on some factor of the structural patterning, in time, of the experimental sounds. Present evidence also indicates that the observed response differentials noted during experiments were the result of a slight, but important, difference in at least one typical parameter, i.e., the pulse interval.
A Comparison of Transmitter and Synephrine on Luminescence Induction in the Firefly Larva
Authors: Carlson Albert D. 
Published: April 2021

ABSTRACT
The pharmacological effects of neural transmitter and synephrine are compared with respect to induction of luminescence in extirpated larval firefly lanterns. Transmitter and synephrine show many similarities of action. They are as follows : They both act directly on the lantern. Their response latencies are relatively constant. Both stimulate ATP production. Neither induces a persistent intermediate in anoxic lanterns. No monoamine oxidase enzyme appears to act on them. The luminescence-inducing action of both is rapidly blocked by chlorpromazine. They show identical responses in the presence of dichloroisoproterenol. Luminescence induced by transmitter is much more rapidly extinguished than that induced by synephrine. The possible reasons for the difference in luminescence extinction rate between the two agents are discussed and their different modes of delivery are emphasized.
Factors Affecting Diastolic Blood Pressures in the Systemic and Pulmocutaneous Arches of Anuran Amphibia
Authors: Jones David R. , Shelton Graham 
Published: April 2021

ABSTRACT
During rhythmic lung ventilation systolic blood pressures in the pulmocutaneous and systemicarches were more or less the same although diastolic pressures in the former were some 3– 4 cm H2O lower than in the latter. During prolonged apnoea (20– 35 min) the pulse pressures became identical. Venous pressures in both lung and body circuits were little affected by these procedures. Raising or reducing systolic pressure by application of drugs to the exposed ventricle caused no change in the relationships of the pressure pulses in the systemic and pulmocutaneous arches. Removal of the conus arteriosus and spiral valve caused a significant reduction in diastolic pressure in the systemic but not in the pulmocutaneous arch. After conus removal differences in diastolic pressures in the systemic and pulmocutaneous arches were only recorded when valves at the apex of the conus were functional. Bilateral occlusion of both systemic arches produced a greater increase in systolic blood pressure in the systemic and pulmocutaneous arches than bilateral occlusion of the pulmocutaneous arches, although pressure changes following the latter were more variable. Blood flow in the pulmocutaneous arch was extremely variable, lowest stroke flows being recorded when the pressure pulses in the systemic and pulmocutaneous arches were identical. The role of the conus arteriosus, spiral valve, arterial compliance and peripheral resistance in maintenance of diastolic pressures in the systemic and pulmocutaneous arches is discussed.
The Influence of Environmental Salinity on the Water Fluxes of the Amphipod Crustacean Gammarus Duebeni
Authors: Lockwood A. P. M. , Inman C. B. E. , Courtenay T. H. 
Published: April 2021

ABSTRACT
It has been known for a number of years that removal of the eyestalks of decapod crustaceans disturbs the maintenance of the water balance of the animals during and after ecdysis (Scudamore, 1947; Carlisle, 1955; Passano & Jyssum, 1963; Bliss, Wang & Martinez, 1966). More recently it has been shown that ligaturing or removal of the eyestalks of crayfish (Procambarus clarkii) results in an increased urine output and this has been interpreted as indicating an increase in permeability to water at the body surface (Kamemoto & Ono, 1967). The semi-terrestrial crab Metopograpsus messor shows a similar effect (Kato & Kamemoto, 1969).
Statocyst-Induced Eye Movements in the Crab Scylla Serrata*
Authors: Sandeman D. C. , Okajima A. 
Published: April 2021

ABSTRACT
The fast and slow eye movements of nystagmus in crabs can be produced by moving a striped pattern around the animal or by rotating the animal in complete darkness. The discharges in the eye muscles are the same regardless of the method used to produce nystagmus. Controlled irrigation of the statocyst in isolated eye-brain preparations of the crab produces activity in the eye muscles which is equivalent to the slow and fast phases of normal nystagmus. When stimulated together, both statocysts combine to produce a greater excitation of the appropriate eye muscles than that produced by the stimulation of a single statocyst. Anticlockwise rotation of the fluid in the left statocyst produces greater muscle activity than clockwise rotation of the fluid in that statocyst. Clockwise rotation of the fluid in the right statocyst is more effective than anticlockwise rotation in the right statocyst. In a model of the system the mutual inhibitory effect between the systems driving the eyes in opposite directions is placed on the output side. The fast-phase system operates through the slow-phase systems, driving one side vigorously while inhibiting the other.