bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Physiology of Excretion in the Cotton Stainer, Dysdercus Fasciatus Signoret: II. Inorganic Excretion and Ionic Regulation
Authors: Berridge M. J. 
Published: April 2021

ABSTRACT
Inorganic excretion has been studied during both phases of excretion. Large amounts of potassium, magnesium and phosphate are excreted during the first phase, but sodium and chloride losses are reduced to a minimum. There is a close correlation between inorganic excretion and the relative abundance of these ions in the diet. The inorganic ion and total nitrogen content of the urine retained in the rectum during the post-excretory phase shows little change. This provides strong evidence for assuming that the Malpighian tubules are inactive during this period. Magnesium, potassium and calcium concentrations in the haemolymph remain relatively constant; sodium and chloride concentrations, however, show a marked increase during the middle of the instar. Amino acid concentration compensates for these changes, so ensuring a constant osmotic pressure in the haemolymph. The high rate of liquid excretion in Dysdercus probably results from an excessive intake of inorganic ions.
The Physiology of A Lepidopteran Muscle Receptor
Authors: Weevers R. De G. 
Published: April 2021

ABSTRACTStimulation of the pupal receptor muscle via its nerve resulted in an increased sensory discharge frequency from the MRO. The extent of this excitation was similar in haemolymph and in pupal saline. Stimulation of an MRO whose connexions with the C.N.s. were intact resulted in a transient reflex inhibition of the tonic discharge in the RM of the stimulated receptor. Cessation of sensory stimulation resulted in a transient elevation of RM tone in the stimulated receptor. These changes would tend to protect the sense organ during rapid stretching and would also ‘take up the slack’ when it was released. A slight crossed intrasegmental RM reflex is described which would normally reinforce the ipsilateral reflex. No RM reflexes were found in adjacent segments. These results are discussed in relation to the nature of the deformation occurring in the sensory dendrites, and in relation to the function of RM systems generally.I am very grateful to my supervisor, Prof. G. M. Hughes for his guidance during the course of this work and to the D.S.I.R. for financial support in the form of a Research Studentship.
Studies On the Renal Excretion of Electrolytes By the Trout (Salmo Gairdneri)*
Authors: Holmes W. N. , Stainer I. M. 
Published: April 2021

ABSTRACT
A decline in the renal excretory rates of water and electrolytes occurred in the trout, Salmo gairdneri, at the time of smolting. This decline appeared to be almost entirely attributable to a reduction in the glomerular filtration rate. Although there was an increase in the total urine osmolal concentration as the urine flow decreased, this decrease was insufficient to maintain the total osmolal excretory rate at a constant level. The sodium, potassium and chloride concentrations of the urine only accounted for approximately 50% of the observed real osmolality of the urine in both the smolting and the non-smolting fish; the difference may have been due to the presence of osmotically active nitrogenous compounds. No selective change in the tubular reabsorptive or secretory processes were found to accompany the reduction in glomerular filtration at the time of smolting. The urine:plasma-ion concentration ratios showed no evidence for any selective concentration in the renal tubule. During the transition from the smolting to the post-smolting condition the renal excretory pattern was restored to that of the pre-smolting trout. The possible significance of these changes in relation to the excretory changes known to occur during the adaptation of salmonid fishes to a marine environment are discussed.
Observations On the Burrowing of Arenicola Marina (L.)
Authors: Trueman E. R. 
Published: April 2021

ABSTRACT
Continuous recordings of the hydrostatic pressure in the coelom of Arenicola marina show a resting pressure of about 2 cm. of water in a non-burrowing worm. During burrowing a series of pressure peaks is produced and these gradually increase in amplitude up to 110 cm. as burrowing progresses. The pressure peaks are of 2 sec. duration, occur at intervals of 5-7 sec., and for each there is a major contraction of the circular muscles followed by the shortening of the longitudinal muscles. The main power stroke in producing the high pressure is the contraction of the longitudinal muscles of most of the trunk segments. The sequence of muscular contractions and the phases of burrowing are considered. The pressure is utilized at the anterior end of the worm both to aid passage through the sand and to anchor the head while the posterior segments are pulled into the burrow. At maximum pressures the tension developed in the circular muscle of the body wall is estimated to be 3 kg./cm.2, while the resting pressure corresponds to less than 7% of this.
Optokinetic Memory in the Crab, Carcinus
Authors: Horridge G. A. 
Published: April 2021

ABSTRACT
For many lower animals the optokinetic response of the eye or head to a movement of the whole visual field is a useful indication that the. movement has been seen. The lower velocity limit of the optokinetic response is extraordinarily low in some animals. In the dog, ter Braak (1936) reports responses to drum movements at 6·4°/hr., which is comparable to the lower limit in the crab. The question arises as to whether a memory of successive positions is involved.
Perception of Edges Versus Areas by the Crab Carcinus
Authors: Horridge G. A. 
Published: April 2021

ABSTRACT
The previous paper (Horridge, 1966) showed that a crab gives a directional eyestalk response to a striped drum which has been moved during a dark period. The crab’s ability to do this shows that the former position of the stripes is remembered in some way for many minutes in the dark and is correlated with the new position on re-illumination. In that paper two aspects were omitted for simplicity. It was assumed that the crab perceives the stripes much as we do as areas of black and white, and that eye tremor can be ignored. In the present account it will be shown that neither of these assumptions is justified, and that both must be modified by one new fact, that eye tremor accentuates the perception of edges.
Optokinetic Memory in the Locust
Authors: Horridge G. A. 
Published: April 2021

ABSTRACT
Having established that a crab can retain a visual impression of the positions of contrasting stripes in its visual field for a period of many minutes in the dark with an accuracy of about over short periods, it became of immediate interest to know whether other arthropods can do the same. The same technique as in the previous papers (Horridge, 1966a) was therefore applied to the locust as a convenient large insect. The locust is especially appropriate in that we have information on the electrophysiology of the visual system (Horridge, Scholes, Shaw & Tunstall, 1965) and on the optomotor response to moving striped drums (Thorson, 1965). The question is of interest not only for comparative purposes but because for further analysis of some aspects of optokinetic memory an insect is more likely to be of value than a crab as an experimental animal.
Optokinetic Responses of the Crab, Carcinus to A Single Moving Light
Authors: Horridge G. A. 
Published: April 2021

ABSTRACT
In all measurements of the optokinetic response, with a wide significance in the analysis of the visual system, especially in arthropods, the stimulus of preference has been the striped drum. The reason is that the responses are then large and obvious and the striped drum is easy to set up experimentally, at least in its simplest form. However, striped drums have disadvantages : they cannot be switched instantaneously from one position to another; they move in only one plane; they are difficult to manufacture without subharmonics which arise from unequal illumination or faults in the stripes; they stimulate all exposed parts of the eye simultaneously and many eyes have different properties in different areas; they have upper and lower edges; centres which cannot be aligned with both eyes, and cannot easily be reproduced to exact specification.
Visceral Afferent Signals in the Crayfish Stomatogastric Ganglion
Authors: Larimer James L. , Kennedy Donald 
Published: April 2021

ABSTRACT
The crayfish stomatogastric ganglion (SG) contains about twenty-five neurone somata; it supplies motor innervation for the anterior gut, and receives afferent input from mechanoreceptors associated with the stomach. Its proximal branches respond to normal stomach contractions with a complex, patterned, centrally directed discharge involving several units. Discharges from the largest of these can be recorded nearly simultaneously in the two superior oesophageal (proximal) and the two lateral (distal) nerves from SG. In preparations with these lateral nerves connected to the stomach the cell shows constant-frequency spontaneous activity, which can be reset by direct stimulation of any one of the four branches. Mechanical stimulation of the cardiac ossicles evokes a burst discharge. Simultaneous recording from the two lateral nerves shows that impulses in one of them consistently occur earlier; this temporal relationship is preserved when the leading side is stimulated, but reverses (usually accompanied by polarity changes) when the other is stimulated. Each lateral branch continues to respond independently after being cut at its point of entry into SG. It is concluded that the cell is a new type of receptor neurone, with a bifurcating axon and two dendrites, each autogenically active at its receptor terminal. The higher-frequency input always determines the output rhythm. A cell with the appropriate configuration was figured by Orlov (1927) from methylene blue-stained SG preparations.
Micropuncture Studies of Formed-Body Secretion by the Excretory Organs of the Crayfish, Frog and Stick Insect
Authors: Riegel J. A. 
Published: April 2021

ABSTRACT
Formed bodies, similar to the spheroids of the crayfish antennal gland, are present in urine removed from the frog nephron and from the insect Malpighian tubule by micropuncture. The formed bodies contain digestive enzymes and appear to function in the digestion of materials accumulated by the cells of the proximal portions of these excretory organs. These results indicate that some concepts regarding the process of urine formation in animals are in need of reappraisal. It is possible that in the crayfish and other animals with filtration kidneys only very small molecules are filtered. In the Malpighian tubule the secretory basis of urine formation may be more firmly established. However, whether or not organic materials enter the urine by passive diffusion may be in need of reinvestigation.
Factors Affecting the Recovery from Diving Bradycardia in the Frog
Authors: Jones D. R. 
Published: April 2021

ABSTRACT
Recovery from diving bradycardia is not prevented by allowing a frog to surface into nitrogen or excess carbon dioxide. Artificial respiration performed during submersion causes an immediate increase in heart rate whether the lungs are filled with air or nitrogen. The initial rapid increase in heart rate is prevented by bilateral vagotomy but is unaffected by section of the sympathetic connexion to the heart. Spike activity in the pulmonary vagus increases as the lungs are filled. A burst of activity frequently occurs in the cardiac vagus during this period. The heart rate increases as the cardiac vagus becomes quiet. Activity continues in the pulmonary branch until deflation of the lungs. The suggestion is made that the initial rapid increase in heart rate following artificial respiration or on surfacing is due to a decrease in parasympathetic inhibitory activity, by an interaction from either proprioceptors in the lungs or presso-receptors in the walls of the atria or veins.
The Photopositive Response of the Frog (Rana Pipiens) Under Photopic and Scotopic Conditions
Authors: Muntz W. R. A. 
Published: April 2021

ABSTRACTUnder suitable experimental conditions (Boycott, Mrosovsky & Muntz, 1964) frogs jump towards the light (Pearse, 1910; Muntz, 1962b). This response, which is released most readily by blue light, appears to be a function of the retinal projection to the diencephalon (Muntz, 1962a, b). The responsiveness to blue is very marked, and is largely independent of the intensity and saturation of the stimulating lights. It was also possible to show that inhibition was involved, since adding green light to blue reduced its effectiveness (Muntz, 1962b). As a result of further experiments (Muntz, 1963 a, b), it was suggested that the response was due to a synergistic action of the green rods and the cones, opposed by an inhibitory action from the red rods. This hypothesis is described in more detail in the Discussion.
Facilitation in the Rapid Response of the Earthworm, Lumbricus Terrestris L
Authors: Roberts M. B. V. 
Published: April 2021

ABSTRACT
Successive rapid responses of the earthworm show a marked tendency to increase in size on repetition. It is shown that this ‘staircase’ phenomenon is not due to peripheral facilitation either on the afferent or efferent side of the reflex, but to summation in the nerve cord and evidence is presented that it occurs at ‘giant-to-motor’ junctions. Facilitation is most pronounced in preparations whose ‘giant-to-motor’ junctions are accommodated. In such cases a single impulse in the median giant fibre is ineffective, two or more being required to produce a rapid response throughout the length of the animal. Fatigue and facilitation in the earthworm is discussed in relation to similar phenomena in other invertebrates.
The Acoustic Behaviour of the Bush Cricket Pholidoptera Griseoaptera
Authors: Jones M. D. R. 
Published: April 2021

ABSTRACT
Pholidoptera griseoptera males singing alone or alternating with other males produce short chirps of three or occasionally four syllables (wing movements) lasting about 100 msec, (at 180 C.). Close proximity of singing males may result in rivalry behaviour where chirps lasting up to about 4 sec. may be produced. The long chirp is not usually continuous but has a number of breaks or ‘stutters’. The syllables and syllable rates in the long chirp and short chirp are essentially similar. At the end of a short chirp or of a group of syllables in the long chirp, the syllable rate is decreased, possibly indicating a waning of excitation of the syllable-producing mechanism. Males within hearing range of each other alternate or occasionally synchronize their short chirps. The pattern of this interaction appears to be determined mainly by mutual inhibition between the singing males. Mutual excitation may cause an increase in chirp rate during the interaction. Chirping may be controlled by a pacemaker system which can be inhibited or excited by its various inputs. A long chirp is possibly the result of a high level of excitation of this mechanism. Alternation singing and rivalry behaviour between males may have a territorial significance.
The Neuromuscular Mechanism of Stridulation in Crickets (Orthoptera: Gryllidae)
Authors: Bentley David R. , Kutsch Wolfram 
Published: April 2021

ABSTRACTThe neuromuscular mechanism of stridulation has been studied in four species of field crickets. The operation of the exoskeleton has been investigated by direct and neurona-stimulation of muscles and by manipulation of the isolated exoskeleton ; the wings are closed by lowering the tergum and opened by subalar, basalar and tergopleural sclerites acting outside the wing pivot. Muscle action potentials recorded from freely moving animals during stridula tion show the following: (a) In the calling or aggressive song pulses, the closing stroke is produced by the medial dorsoventral muscles; the opening stroke is produced by the basalars and subalars.(b) The ‘tick’ of the courtship song is produced by simultaneous contraction of the medial dorsoventral muscles; the subalars and some of the basalars are active during the soft pulse phase of the courtship song but not during the ‘tick’.(c) Evidently, the first dorsal longitudinal is active during the ‘tick’ and closing; the second is active in opening and in the soft pulse phase of courtship. The upstroke of flight is homologous to the closing stroke of stridulation.
The Acoustic Behaviour of the Bush Cricket Pholidoptera Griseoaptera
Authors: Jones M. D. R. 
Published: April 2021

ABSTRACT
Artificial signals have an inhibitory effect on chirping which affects whole chirps. With signals 1 sec. or less in length, the insects hardly ever chirp during the signal. If the signal is longer, chirps ‘break through’, but the chirp rate is usually less during the signals than in the periods of silence between the signals. With signals of 0·1 sec. or less, the insect does not chirp until 0·4−1·0 sec. after the end of the signal. With longer signals this interval is reduced until the insect chirps during the signal. Artificial signals may have an excitatory effect in increasing the total chirp rate in the period during which signals are being produced, and this effect may last for several minutes after the signals have ended. This may be due to rebound from inhibition or to a parallel excitatory effect of the signal. The excitatory effect is increased if the length of the signal is increased from 0·1 to 1 sec. The excitatory effect is not so certain as the inhibitory effect and sometimes may be reversed, giving a reduction in chirp rate. With very long signals (3 min.) there may be (a) a decrease in chirp rate during the signal followed by an increase after the signal, (b) a decrease in chirp rate during the signal with a very slow recovery after the signal, or (c) an increase in chirp rate during the signal followed by a decrease to normal after the signal. These effects can be more easily explained by parallel excitatory and inhibitory effects than by rebound from inhibition. An increase in intensity of the signal from 40 to 70 db. gives an increase in both the inhibitory and the excitatory (or depressant) effects of the signals. The rapidity and certainty of the inhibitory effect make it seem probable that few synapses are involved. The greater flexibility of the excitatory effect indicates that this effect may be mediated by higher centres in the c.N.s. Recognition of the characteristic chirp of the species does not appear to be particularly important in the acoustic interaction of Ph. griseoaptera males.
The Metabolic Effects of the Corpus Allatum Hormone in the Male Desert Locust
Authors: Odhiambo Thomas R. 
Published: April 2021

ABSTRACTAn account is given of the pattern and intensity of the spontaneous locomotor activity of adult males of the desert locust. It is shown that desert locusts exhibit almost continuous activity under continuous fight conditions, and almost continuous inactivity in darkness. Under alternating light and dark conditions, the locusts assume a periodicity of activity which is not circadian since it may be ‘instantaneously’ changed by altering the light/dark régime. Allatectomy of newly emerged adult locusts results in their persistent locomotor inactivity, which may be reversed by implanting active corpora allata. Allatectomy of sexually mature locusts similarly leads to inactivity. Gonadectomy has no such effect on locomotor activity. The hypothesis is advanced that the corpus allatum hormone regulates the intensity of locomotor activity by its direct effect on the central nervous system. The accumulation of fat and glycogen after allatectomy may thus be explained as a consequence of the resulting lowered spontaneous locomotor activity since fat forms the chief energy reserves in the desert locust.
Membrane Potentials in Amoeba Proteus
Authors: Bingley M. S. 
Published: April 2021

ABSTRACT
Amoebae can be penetrated by microelectrodes at either end. One records voltage and the other supplies alternating current. Step-like increases in alternating voltage superimposed on potentials recorded by the voltage electrode when in either the pseudopod or rear region demonstrate that low potentials recorded from a pseudopod and high ones from the rear region exist across a discrete impedance barrier. The only structure so far shown to fulfil this function is the plasma membrane. A resistance inserted in the earth path monitors current flowing through the system and confirms observations made when recording with single electrodes that there is a reduction of electrode resistance when the cell is entered. Pronounced depolarization in the rear region is shown when the currentcarrying electrode penetrates the pseudopod, but not vice versa. Morphological changes associated with membrane potential reversal are illustrated. Consideration is given to the role of step-like potential changes in movement.
Neuromuscular Mechanisms of Burrow Irrigation in the Echiuroid Worm Urechis Caupo Fisher & Macginitie
Authors: Lawry James V. 
Published: April 2021

ABSTRACT
This paper describes a neurophysiological investigation of the initiation and co-ordination of the peristaltic waves in Urechis. Peristaltic waves are (a) initiated in the proboscis and propagated posteriorly, and (b) initiated in the hind gut and propagated anteriorly, provided that nerve cord, body-wall and peripheral nerves are intact. There is a hierarchy of pacemaker regions in the nerve cord, effective over lengths as small as 30 mm. This hierarchy is normally dominated by the pacemaker in the proboscis. The pacemakers respond with increased frequency to oxygen, epinephrine and acetylcholine in concentrations of 10−6 M. Eserine potentiates the acetylcholine response. The system is insensitive to 5-hydroxytryptamine. The giant fibres conduct at 1·5 m./sec. and mediate a startle response; they are not involved in the conduction of the peristaltic wave.
Photoperiodic Control of Diapause Induction in the Larva of Lucilia Caesar L. (Diptera: Calliphoridae)
Authors: Ring R. A. 
Published: April 2021

ABSTRACT
It has been shown that photoperiod has a direct effect on the larva of Lucilia casear L. in the induction of diapause. Transference of larvae from long to short photoperiod conditions during the 1st, 2nd, or 3rd instar increases their tendency to enter diapause. Conversely, transfer from short to long photoperiod conditions decreases their tendency to enter diapause. Larvae are sensitive to changes in the absolute length of the photoperiod during all instars. The reaction is not restricted to any one stage but tends to be cumulative; thus the earlier the larvae are transferred from one photoperiod regime to another then the greater the contrast in diapause incidence between experimental groups and controls.
Studies on the Effects of the Removal of the Frontal Ganglion in Locusta Migratoria L
Authors: Clarke Kenneth U. , Gillott Cedric 
Published: April 2021

ABSTRACT
A cytochemical investigation was made of the RNA content of the cells of the mid-gut, fat body and epidermis in third- and fourth-instar Locusta migratoria L. from which the frontal ganglion had been removed, in control operated and in starved animals. In operated locusts the nucleus was smaller, the nucleoli small or absent, and the cytoplasmic RNA much less than that found in operated controls. No differences were observed in the DNA content of the cells. Autoradiograph studies were made of the uptake of 3H-uridine into the cells of operated and control operated locusts. In operated locusts the appearance of labelled uridine in the nucleus was delayed, the rate of uptake slower, and the total amount incorporated less (never more than 25%) than in the controls. Studies were made of the uptake of 14C-uridine into the nuclei of operated and control-operated locusts. Nuclei were isolated from locusts killed at known times after the isotope had been injected and their radioactivity was measured. The results confirmed those found in the radioautographic studies. The significance of these results is considered in the light of the Jacob & Monod model of the control of protein synthesis.