bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Shadow Reaction of Diadema Antillarum Philippi
Authors: Millott N. , Yoshida M. 
Published: April 2021

ABSTRACT
Isolated pieces of test of Diadema bearing a single spine show responses to a constant shadow cast on the radial nerve which are consistent in reaction time, duration, amplitude and frequency of the contractions. Variations in the intensity and duration of the lighting which precedes the shadow exert similar effects on the whole reaction, affecting all the above features. Variations in the duration and intensity (% decrease in intensity of illumination) of the shadow differ in their effects. The intensity affects all the features of the whole reaction, but the duration affects only the later part. The differing effects of light and shade suggest that the shadow response may be a rebound from inhibition due to light which, when re-admitted, diminishes any shadow reaction that may be in progress.
The Cuticular Pattern in an Insect—The Intersegmental Membranes
Authors: Locke M. 
Published: April 2021

ABSTRACT
Grafts including intersegmental membrane have confirmed the existence of a segmentally repeating gradient of incompatibility in the integument of Rhodnius. When host and graft influence one another the pattern can be predicted from the interaction of the gradients. When a graft is uninfluenced by the host the anterior part of the graft is dominant in restoring pattern continuity. The intersegmental membranes are neutral with respect to the gradient behaviour. The gradient is not restricted to the area forming the ripple pattern but includes other patterns in the abdomen.
Responses of the Heliozoon Actinophrys Sol to Prey, to Mechanical Stimulation, and to Solutions of Proteins and Certain Other Substances
Authors: Kitching J. A. 
Published: April 2021

ABSTRACT
Various flagellates and small ciliates stick to the axopods of Actinophrys. Contact with the base of an axopod or with the body surface leads to the outgrowth of a food funnel, by which the prey is ultimately surrounded. If a fine probe or micropipette touches the body surface or the base of an axopod, a small cup may grow out over it, investing it closely, but the instrument is soon released. A squirt of tap water from a micropipette may also provoke the outgrowth of a small lobe or cup, or local pinocytosis. Contact with, or a squirt from, a micropipette containing a solution of egg albumin provokes a more extensive reaction. The micropipette usually becomes invested extensively. The micropipette is drawn into the body and held there for up to an hour. Immersion in egg albumin solution leads to a temporary spreading and lobulation of the axopod bases, and later a ‘skin’ may separate from the body surface. Skin formation is more pronounced in serum albumin solution, and may also be induced by y-globulins and gelatin. On treatment in vivo with toluidine blue or thionine a violet layer in the body surface separates as a pinkish violet or violet skin, leaving the body surface unstained. There is evidence that the skin-forming substance is associated directly or indirectly with the maintenance of cell shape.
Neuromuscular Activity in the Swimming Sea Anemone, Stomphia Coccinea (Muller)*
Authors: Hoyle G. 
Published: April 2021

ABSTRACT
The spontaneous activity and also the response mechanisms to externally applied electric shocks have been studied in the swimming sea anemone Stomphia coccinea obtained from Puget Sound, Washington. Slow rhythmical activity with a repetition interval of the order of 30 min. is evident in kymograph records of whole-animal movements and also in rings of body wall isolated from the oral or basal regions. By suitably placing the stimulating electrodes different parts of the musculature can be brought into contraction. Those studied were principally the parieto-basilar muscles and also the longitudinal retractors, the circular muscles of the column and the isolated oral sphincter. The magnitude of the response of the parieto-basilar muscles to constantstrength stimuli was very variable. Responses occur to single shocks and these increase in magnitude with increasing strength of stimulus. The parietal muscles give delayed, slow contractions in response to trains of about ten stimuli at one per sec. The isolated sphincter muscle shows two kinds of contraction, a quick one which occurs to single shocks and a slow one which occurs following a brief train of fairly widely separated shocks. The ordinary circular muscles respond with a slow contraction to a few widely spaced shocks. They do not give quick contractions. Although in many cases animals responded to eight quick shocks by giving swimming reactions this number was not found to be a precise requirement, and it varied for the same animal at different times in an unpredictable manner as well as varying from one animal to another. On one occasion a swimming response occurred after a single shock and on another after twenty-eight shocks. It was found that the state of ‘facilitation’ (occurring in the response to electric shocks) of the muscles used in swimming varied a great deal but did not show any marked long-term change following a single shock or the elicitation of a swimming response.
The Reflex Co-Ordination of the Heart Beat with Respiration in the Dogfish
Authors: Satchell G. H. 
Published: April 2021

ABSTRACT
The hearts of Squalus lebruni and Mustelus antarcticus beat at intervals that approximate to some simple multiple (1-4) of respiratory cycle length. The beat tends to be initiated during a particular phase of the respiratory cycle, most commonly just before or just after the opening of the mouth. Possible mechanisms of this co-ordination are considered and evidence is presented to show that it is reflexly mediated. Fibres from receptors fired by pharyngeal dilatation are believed to constitute the afferent limb, and the cardiac vagi the efferent limb of the reflex arc. Simultaneous records of blood pressure have been made from the 1st afferent branchial artery and the coeliac artery. By subtraction, the differential pressure across the gill vessels has been calculated and found to have a peak early in the cardiac cycle. Simultaneous photo-electric records of gill opacity and branchial blood pressure show the gill vessels to be compliant. It is concluded that there is a brief period of rapid blood flow early in each cardiac cycle. Calculations from simultaneous records of the electrocardiogram and branchial blood pressure showed that heart beats originating near the time of mouth opening caused a rapid flow of blood through the gills at the time that water was expelled across them. It is suggested that this synchronization of the periods of rapid flow of blood and water serves to maintain the diffusion gradient of oxygen across the gill epithelium.
The Arginase Activity of the Tissues of the Earthworms Lumbricus Terrestris L., and Eisenia Foetida (Savigny)
Authors: Needham A. E. 
Published: April 2021

ABSTRACT
The difference in arginase activity between the tissues of Eisenia and those of Lumbricus shows a relationship to the difference in urea output by living worms of the two species under the same dietary regime. In Eisenia the difference in activity between the tissues of fasting and feeding worms is much smaller than in Lumbricus. The specific outputs of urea by living, fasting and feeding worms likewise differ less than in Lumbricus. These facts strengthen previous evidence in favour of a Krebs-Henseleit type of mechanism for urea production in earthworms. In Eisenia the difference in arginase activity between gut and body wall is similar to, but smaller than, that in Lumbricus, and the body wall makes a major contribution to the total activity. The combined concentrations of ammonia-, amino-, and urea-nitrogen initially present in homogenates of the tissues of these worms are proportional to the combined amounts of the three components excreted per unit weight by living worms of the same species and regime. The two species differ in a number of other properties investigated.
Experiments on the Influence of Light on the Behaviour of Polyzoan Larvae
Authors: Ryland J. S. 
Published: April 2021

ABSTRACT
An apparatus is described for investigating the photic responses of marine larvae. A parallel beam of light is projected along horizontal Perspex troughs containing the larvae, while the use of a water bath prevents their being subjected to a rise in temperature. Using a light beam of 5000 lux at normal summer sea temperatures, plotting the positions of the larvae in the troughs at regular intervals has revealed four types of behaviour : I. Larvae at first all photopositive, later all becoming photonegative ; for example, Celleporella hyalina. II. Larvae at first all photopositive, only a small proportion of them later becoming photonegative ; for example, Bugula neritina. III. Larvae photopositive throughout the length of their natant phase; for example, Flustrellidra hispida. IV. Larvae showing no response at all to directional illumination ; for example, Alcyonidium polyoum. It has been shown that the reversal of the sign of reaction to light in Celleporella hyalina larvae is dependent on the passage of time; it does not require their exposure to a certain amount of light for its inception. When disks cut from Fucus serratus fronds were placed in the troughs as a substrate for settlement, the majority of Celleporella hyalina larvae developed a photonegative reaction before they metamorphosed. Horizontally and vertically placed panels in the Menai Straits received settlement of polyzoans on all surfaces free from sediment and dense algal cover. These adverse factors would have masked any selection based on the behavioural responses of the larvae. Laboratory experiments with opaque panels suspended vertically, obliquely and horizontally have shown that Celleporella hyalina larvae settle on the side away from the light. Thus they normally settle on the undersurfaces of horizontal and oblique panels, but this pattern is reversed if the panels are lit from below. Settlement on panels in the sea would therefore seem to depend on the reactions of larvae to light as well as on the unfavourability of upward-facing surfaces. The nature of the larval responses is discussed.
The Mode of Operation of the Electric Receptors in Gymnarchus Niloticus
Authors: Machin K. E. , Lissmann H. W. 
Published: April 2021

ABSTRACT
Two possible modes of action of the electric receptors of Gymnarchus niloticus are described. In one, received pulses are ‘smoothed’ and a sensory discharge occurs dependent only on the smoothed level (‘pulse-frequency-modulation’). According to the other mechanism, sensory nerve impulses are produced at the same frequency as the received pulses, but after a delay dependent on their amplitude (‘pulse-phase-modulation’). An experiment has been devised to distinguish between the two mechanisms, and, if the pulse-frequency-modulation mechanism is the operative one, to measure the smoothing time-constant. The results favour the pulse-frequency-modulation mechanism, and indicate a smoothing time-constant of 25 msec. It appears also that adaptation takes place in the electric receptors. The origin of the smoothing action is discussed. The sensitivity of electric receptors is compared with that of other sense organs.
Studies on Ionic Regulation in Carcinus Maenas (L.)
Authors: Shaw J. 
Published: April 2021

ABSTRACT
The mechanism of sodium balance in Carcinus maenas has been investigated. Measurements of sodium outflux showed no evidence of a decrease in surface permeability to sodium in dilute sea water. The rate of urine production in normal sea water was 3·6% body weight per day and the sodium loss through the urine was insignificant compared with the total sodium loss. In 40% sea water the urine rate was increased to 30% body weight per day and the loss in the urine accounted for 20 % of the total loss. Measurements of sodium influx and calculation of the active component showed that the active uptake mechanism was fully saturated at all external concentrations in which the animals could survive. Regulation of the blood sodium concentration is effected largely by the activation of the sodium uptake mechanism. This prevents the blood concentration falling below a critical level as long as the external concentration itself is not too low.
Fuel Utilization and Duration of Tethered Flight in Aphis Fabae Scop
Authors: Cockbain A. J. 
Published: April 2021

ABSTRACT
Fat contents (ether extracts) of unflown 24 hr. old alatae of Aphis fabae Scop., from different host plants, range from 3−12% of the live weight and 9−33 % of the dry weight. Glycogen contents of alatae reared in culture range from 0·5−1 % of the live weight and 1·7−3·4% of the dry weight. Both fat and glycogen are consumed during tethered flight. Glycogen is used during early flight and fat is the principal fuel after the first hour, when it is consumed at a mean rate of 0·005 mg./aphid/hr. and provides about 90 % of the energy for a 6 hr. flight. The amounts of glycogen in laboratory-reared aphids alone could not maintain flight for more than 34 hr. Metabolic rates during tethered flight range from 52 to 66 cal./g. live wt./hr. or 11−14ml. O2/g./hr. The flight muscles constitute about 13% of the live body weight of 24 hr. old aphids, and, attributing most of the metabolism during flight to these muscles, their metabolic rates range from 400 to 500 cal./g./hr. Flight capacity of 24 hr. old aphids at 25−26°C. is directly related to initial fat content and varies between 3 and 8 hr. in aphids from culture (mean of 4 % fat by live weight) and between 7 and 12 hr. in aphids from the field (10% fat). Flight fatigue occurs before all the fat reserves are used; possibly fat stored in parts of the body remote from the flight muscles cannot be mobilized rapidly enough to support continuous flight. Fat and glycogen reserves occur mainly in the fat-body cells of the thorax and abdomen; fat also occurs between the fibrils of the indirect flight muscles and glycogen along the surface of the fibres. Flight-exhausted insects have little or no fat in the thorax, but small deposits remain in the abdomen; little glycogen can be detected in culture aphids flown to exhaustion.
The Response of A Hydroid to Weak Water-Borne Disturbances
Authors: Josephson Robert K. 
Published: April 2021

ABSTRACT
Syncoryne mirabilis polyps rapidly bend toward the source of a mechanical disturbance in their vicinity. A small moving copepod a few millimeters from the polyp creates sufficient stimulus to evoke this response. The hydroid will respond to a mechanical pulse from an electrically driven prodder as well as to single movements of the prodder either toward or away from the polyp. With the prodder 0.5 mm. from the polyp mid-line, threshold displacement of the prodder is only 2.5-3µ. Repeated pulses of increasing amplitude, initially below threshold intensity, will not evoke bending if the frequency is over 5/sec. This means that stimuli which cause no overt response can still inhibit polyp bending to normally supra-threshold subsequent stimuli. A polyp will not respond to slow currents of water, but will bend towards the source of sudden jets of water directed at it. The capitate tentacles are not necessary for the movement perception, but after their removal the threshold is raised and the accuracy of bending reduced. The response does not require that the polyp be attached to a fixed stalk; it also occurs in isolated polyps floating in a density gradient. The hypothesis is presented that polyp bending is due to unequal stimulation of opposite sides of the polyp because of decreasing stimulus intensity with increasing distance from the source of disturbance.
The Mechanism of Orientation of Freely Moving Littorina Littoralis (L.) to Polarized Light
Authors: Charles G. H. 
Published: April 2021

ABSTRACT
The mechanism of orientation of Littorina littoralis (L.) to plane polarized light was investigated by means of a servo-mechanism, whereby the intensity of the polarized light was varied with the orientation of the winkle to the plane of vibration. It was shown that these controlled variations in light intensity augmented or decreased the efficiency of orientation. When the light was altered with change in orientation in a direction which would be expected to counteract the Fresnel reflexion/refraction mechanism a fall in responses to polarized light was observed. Random changes in the light intensity of the polarized beam also interfered with the orientation. The influence of reflected patterns of light and shade from the surroundings on the orientation of L. littoralis to polarized light was investigated with the use of the eye shields and with surfaces of different reflective properties. It was conclusively shown that the winkles could orientate both by direct perception of the plane of vibration by the eyes and to comparatively small differences in light intensity in the pattern of light reflected from the substratum.
Orientational Movements of the Foot of Littorina Species in Relation to the Plane of Vibration of Polarized Light
Authors: Charles G. H. 
Published: April 2021

ABSTRACT
Littorina littoralis (L.), L. saxatilis (L.), L. neritoides (L.) and L. littorea (L.) responded to the plane of vibration (e vector) of polarized light directly incident upon their eyes in the virtual absence of any substrate reflexions. Photonegative winkles orientated parallel with the plane of vibration and photopositive individuals at right angles to this plane. Decrease of the angle of incidence towards zero of polarized light rays incident upon the lens aperture of Littorina littoralis completely destroyed the ability to orientate to the plane of vibration. This can be explained on the basis of a Fresnel reflexion/refraction mechanism of orientation. Unilaterally blinded Littorina littoralis gave just as good an orientation to vertical rays of polarized light as winkles with intact vision. It is concluded that the eyes of Littorina species are capable of detecting the plane of vibration of polarized light directly incident from above by means of a Fresnel reflexion/refraction mechanism, and that orientation does not depend on balanced stimulation of the two eyes.
Effect of Acclimatization to High Temperature on the Blood Chloride, Free Amino Acids and Osmotic Pressure in the Freshwater Field Crab Paratelphusa Sp. and the Freshwater Mussel Lamellidens Marginalis
Authors: Rao Kandula Pampapathi , Ramachandra R. 
Published: April 2021

ABSTRACT
Acclimatization of the freshwater field crab, Paratelphusa, to high temperature results in a decrease in the chloride, free amino acids and osmotic pressure of the blood.
Following similar acclimatization the freshwater mussel, Lamellidens marginalis unlike the crab, shows a considerable increase in the blood chloride as well as the free amino acids, while the total osmotic pressure increases relatively little.
These results are discussed and it is suggested that the ionic and osmotic gradient between the milieu intérieur and the protoplasm of the cells might be important in the metabolic compensation to temperature.
Evidence for Humoral Regulation of Digestive Secretion in the Beetle, Tenebrio Molitor
Authors: Dadd R. H. 
Published: April 2021

ABSTRACT
Midgut protease values of starved adult Tenebrio injected with the blood of recently fed adults were, on average, higher than those of similar recipients of the blood of starved donors, or of untreated starved adults of the same age. A similar increase was found in the recipients of blood of newly-emerged adults. Protease activity failed to develop in the midguts of adults which had been decapitated one day before emergence. If decapitation occurred after emergence, enzyme activity developed, but at a slower rate and to a lower maximal level than in the normal adult. Inhibition of the development of enzyme activity was greater the sooner decapitation followed emergence. A few experiments suggested that injection of the blood of normal newly emerged adults could to some extent rehabilitate the development of enzyme inhibited by pupal decapitation. These observations are discussed in relation to the hypothesis that digestive secretion may be under humoral regulation.
The Waterproofing Mechanism of Arthropods
Authors: Beament J. W. L. 
Published: April 2021

ABSTRACT
The permeability to water of the cuticles of a number of aquatic insects has been measured under conditions of evaporation. The range of rates of evaporation amongst these animals is very great; some adult aquatic beetles are quite as waterproof as more permeable terrestrial insects (caterpillars for example), whereas their larvae would seem to be without specific mechanism for restricting the passage of water. Two methods are described, whereby local differences in permeability may be detected, and from one of these methods it is possible to calculate the permeability/ temperature characteristics of different areas of cuticle of an intact insect. The more impermeable insects have uniform permeability over their entire surfaces; these include adult beetles, and both mature and immature stages of Hemiptera. Larvae of mayflies and of some beetles, which are very permeable to water, likewise show no local differences in permeability. The gills of all the species examined are very permeable to water; those of zygopteran dragonflies are more permeable than the rest of the cuticle at lower temperatures, those of Sialis are much more permeable at all temperatures. The effect of temperature upon permeability has been measured. The more waterproof insects reveal transition phenomena characteristic of organized monolayers of lipid, such as are found in terrestrial insects, but by comparison with them the temperatures at which transition occurs are very low. In particular, the temperature at which adults of Dytiscus and Gyrinus become suddenly more permeable (ca. 25° C.) could obtain in natural circumstances, and the evidence suggests that these animals die through osmotic invasion of water when placed at higher temperatures. Other beetles and aquatic Hemiptera, with higher transition temperatures, survive temperatures above 25° C. These ecological implications are discussed. A transition phenomenon occurs in organized lipid over the main cuticle of Sialis, whereas the more permeable gill shows no evidence of this. There is no evidence for organized lipid on the main cuticle of zygopteran larvae, but the temperature/permeability relations of the general cuticle and of the gill are very different. The absolute permeability, and the shape of the permeability/temperature function, of the cuticle of those insects which have very hydrofuge areas of surface suggest that their waterproofing system consists of only one monolayer of organized lipid, which may be either grease or wax.
On the Regulation of the Respiration in Reptiles
Authors: Nielsen Bodil 
Published: April 2021

ABSTRACT
Ventilation of the lungs accomplished by movements of the ribs is, in the phylogenetic development of the animals, first found in the reptilian class. It may therefore be of interest to investigate the regulation of respiration in this group. The reactions to carbon dioxide and to low oxygen tensions is specially interesting considering the importance of these substances for the respiratory regulation in higher animals and man.
The Responses of Certain Mysids to Changes in Hydrostatic Pressure
Authors: Rice A. L. 
Published: April 2021

ABSTRACT
Four mysid species have been found to exhibit responses to changes in hydrostatic pressure. The orientation of these responses has been observed in normal animals, and also in ones from which the statocysts had been removed. The results have helped to confirm earlier work on mysids, and indicate that at least three mechanisms are involved in orientation in this group. These mechanisms are (a) orientation to gravity via the statocysts, (b) the dorsal light reflex and (c) the general position reflex. One of the species used has been shown to respond to slow pressure changes of the same order as those due to tidal rise and fall, and it is suggested that the pressure responses may be important in the tidal migrations of shallow-water mysids.