bluuebunny/crossref_metadata_2025 huggingface dataset:
Ion and Water Transport in Isolated Intestine of the Marine Teleost, Cottus Scorpius
Authors: House C. R. , Green K.
Published: April 2021

The unidirectional sodium fluxes from mucosa to serosa and from serosa to mucosa have been studied in the isolated small intestine of Cottus scorpius, bathed in Ringer and sulphate Ringer, by use of the isotope 22Na. In addition the unidirectional chloride fluxes have been studied in Ringer and choline Ringer using the isotope 36Cl. In Ringer the mean ± S.E. values of these fluxes have been found to be: for sodium, 8·4+ 0·6 (serosa to mucosa) and 23·9+0·7 (mucosa to serosa) /μequiv. cm. -2 hr. -1 and for chloride, 10-5 ± 0-9 (serosa to mucosa) and 21·9 ± 0·9 (mucosa to serosa) μequiv. cm. -2 hr. -1. In sulphate Ringer the mean ± s.E. values for sodium were 4‘5 ± 0·3 (serosa to mucosa) and 6·8 ± 0·6 (mucosa to serosa) /μequiv. cm. -2 hr. -1 and in choline Ringer the mean ±S.E. values for chloride were 5·1 ± 1·0 (serosa to mucosa) and 5·94 + 0·9 (mucosa to serosa) /μequiv. cm. -2 hr. -1. The respiration rates of pieces of intestine placed in Ringer, sulphate Ringer, choline Ringer and artificial sea water have been measured in a Warburg apparatus. The mean ±S.E. values of oxygen consumption in these media have been found to be 0·4 ± 0·2 (Ringer), 0·3 ± 0·2 (sulphate Ringer), 0·3 ± 0·2 (choline Ringer) and 0·1 ±0·2 (artificial sea water) μ1. O 2/mg. dry weight.hr. The electric potential differences between identical serosal and mucosal media bathing isolated intestines have been measured. The mean + s.E. values of the potential difference in Ringer, sulphate Ringer, choline Ringer and artificial sea water have been found to be +0·6 ± 0·3, +2·2 ± 0·2, + 0·8 ±0·3 and +1·3+ 0·2 mV., respectively (mucosal medium taken as reference). The hydraulic conductivity of the isolated intestine has been found by measuring the change in net water flux arising from the creation of an osmotic gradient across this tissue. Net water flux was measured by the change in weight of normal filled sacs. The mean + s.E. value for this parameter has been found to be 0·22 ± 0·05 μ1/cm. 2 mosmolar. hr. (or 2·4+0·6 cm. sec. -1 atm. -1). It has been found that, when artificial sea water is placed in the lumen of the intestine bathed in Ringer, a net flow of water into the lumen occurs. This net water flux falls to zero at a time dependent on the luminal volume (to be diluted) and, thereafter, a net water flux (mucosa to serosa) is established. The net water movement across isolated intestines bathed on both sides by identical media has been studied. The mean ± s.E. values for net water flux (mucosa to serosa) have been found to be: in Ringer, 8·1±0·8, in sulphate Ringer, 3·6±0·5 and in choline Ringer, 6·7 ± 0·6 µ. cm. -2 hr. -1. The results are interpreted as showing that the net transfer of sodium and chloride ions between identical Ringer solutions is achieved by some process whereby these ions are ‘pumped’ in the form of electrically neutral sodium chloride. It is considered that there is some evidence for the existence of a frictional interaction between sodium chloride and water as they pass across the intestine.
Respiratory Movements in Holothuria Forskali Delle Chiaje
Authors: Newell R. C. , Courtney W. A. M.
Published: April 2021

The respiratory rate of Holothuria forskali has been found to be between 0·0162 and 0·0465 ml. O2/g. dry wt./hr. at 17° C. By separating the water pumped by the cloaca from that in contact with the general body surface it is found that cloacal gas exchange accounts for approximately 60% of the total uptake of oxygen by the animal. Uptake of oxygen through the cloaca occurs only when the pumped water is more than 60−70% saturated with air. At lower concentrations there is no exchange through the respiratory trees and no corresponding increase in absorption through the general body surface. Pumping rhythms in intact H. forskali are described. It is shown that there are three main types. In all types the rate of pumping increases as the oxygen in the pumped water becomes depleted. At concentrations corresponding to 60-70% air-saturation, however, pumping ceases and this coincides with the observed reduction in cloacal gas exchange. It is shown that a period of reduced gas exchange through the cloaca is followed by increased uptake of oxygen when pumping is resumed. Measurements of the coelomic oxygen concentration shows that cessation of pumping is followed by a rise in the oxygen concentration in the coelomic fluid. The function of the coelomic oxygen reservoir is discussed.
The Relative Losses of Sodium in the Urine and Across the Body Surface in the Amphipod, Gammarus Duebeni
Authors: Lockwood A. P. M.
Published: April 2021

The suggestion has previously been made (Lockwood, 1961) that the rapid change from isotonic to hypotonic urine production which occurs when Gammarus duebeni is transferred from a high concentration (100−175 % sea water) to fresh water may subserve the function of slowing the loss of ions from the body. Any such slowing would decrease the rate of fall of the blood concentration and hence allow additional time for the necessary concomitant changes in cellular osmotic pressure to be brought about. The ability to slow the rate of ion loss for this purpose might be of functional significance to this species as it is often found in environments such as salt-marsh pools which may be subject to sudden and extensive variations of salinity.
Urine Formation in A Pulmonate Land Snail, Achatina Fulica
Authors: Martin A. W. , Stewart D. M. , Harrison F. M.
Published: April 2021

Inulin is filtered into the urine of Achatina fulica. The process is not subject to poisoning but water reabsorption may raise the U/B ratio to 2·8. The U/B ratios of substances actively reabsorbed or secreted reaches 1 when transport is poisoned thus verifying filtration as a first step in urine formation. Exogenous urea is excreted by filtration. Glucose is filtered and actively reabsorbed. Reabsorption can be poisoned with phlorizin. Chloride is actively reabsorbed. Phenol red and PAH are actively secreted. The secretory process may be poisoned with dinitrophenol. The clearance of phenol red may be taken as an estimate of blood flow through the kidney, which may reach 5·6 ml./min./kg. in Achatina fulica. The PAH clearance is depressed by simultaneous excretion of phenol red and the quantitative measurements of transport give evidence that the same secretory mechanism is used for both phenol red and PAH.
Muscular Activity During Preparation For Flight in A Beetle
Authors: Leston Dennis , Pringle J. W. S. , White D. C. S.
Published: April 2021

The sound produced during the pre-flight activity of the water beetle Acilius sulcatus (L.) consists of a train of pulses, implying that there is a click mechanism present in the thorax when the wings are folded. The pulse frequency rises as the temperature rises. Analysis of the sound oscillograms reveals some differences from the analogous system in cicadas which can be correlated with differences in anatomy. The sinusoidal (inertial) and pulsed modes of operation of insect fibrillar muscle are alternative ways in which oscillatory activity can be generated. They result from a single property of this type of muscle and occur when it is coupled, respectively, to an inertial or to a clicking load.
The Activity of Single Motor Fibres in Arthropods: I. The Dragonfly Nymph
Authors: Knights Ann
Published: April 2021

Responses to mechanical and electrical stimulation have been investigated in single motor fibres dissected in the segmental nerves of the dragonfly nymph. A large proportion of fibres possessed a background discharge which was often accelerated or inhibited on stimulation. Examples of central inhibition were common. Efferent responses varied in type, delay and regularity, both with the input under stimulation and with the frequency and intensity of the volley. The majority of fibres responded to stimulation of more than one nerve root. In many motor fibres changes in the parameters of stimulation demonstrated a reciprocal relationship between intensity and frequency. An enhanced responsive-ness occurred with frequency increases in the range of 10 −100/sec. indicating a considerable importance of temporal summation/facilitation. The characteristic frequency-sensitivity of motor fibres and the variability of their response patterns are discussed in relation to the control of insect muscle.
Cardiac Output in the Large Cephalopod Octopus Dofleini*
Authors: Johansen Kjell
Published: April 2021

The high level of structural organization displayed by the cardiovascular system of cephalopods promises a similar complexity in its functional organization. In spite of an extensive literature on this subject most of the work is old and inadequate in techniques and experimental procedures (Fuchs, 1895; Fredericq, 1914). The only physiological parameters hitherto recorded of any value for the evaluation of cardiovascular dynamics have been arterial and venous blood pressures (Johansen & Martin, 1962).
Larval Diapause of Maternal Origin: Induction of Diapause in Nasonia Vitripennis (Walk.) (Hymenoptera: Pteromalidae)
Authors: Saunders D. S.
Published: April 2021

The environmental factors responsible for the induction of larval diapause in Nasonia vitripennis are photoperiod, temperature and host deprivation. They are effective during the life of the female parent and not during larval development. Short daylength and low temperature induce females to produce diapause larvae early in reproductive life and long daylength and high temperature avert diapause. Conditions of darkness are ‘intermediate ‘in this respect. The effects of daylength are reversible during the life of the female. Females switch from the production of developing to diapause larvae during their reproductive life, so that a distinct age pattern is apparent. The two strains of Nasonia used in this investigation showed different patterns of diapause production. Although this difference is shown to be under ultimate genetic control, the mechanism of in duction is purely maternal and the males play no part in determining the diapause characteristics of their immediate progeny. Unlike other cases of photoperiodic induction of larval diapause, the mechanism cannot operate solely through the central nervous system and a chemical ‘factor’ (a hormone?) passed from the parent female through the egg to the larva is postulated.
Haemodynamics in Tresus Nuttallii and Certain Other Bivalves
Authors: Smith L. S. , Davis J. C.
Published: April 2021

Blood pressures were measured in the hearts and aortas of several bivalves. Systolic pressures in the ventricles were commonly O-5-2-O mm. Hg, while diastolic pressure was zero. The aortic bulb produced pressures similar to those produced by the ventricle, but beat less frequently and not in synchrony with the ventricle, except in the isolated heart. Pericardial and auricular pressures were normally undetectable, except that small pressure pulses were recorded in the auricle during experimentally produced increases in venous return. Aortic pressure sometimes exceeded ventricular pressure, although unusually strong contractions of the body muscles raised aortic pressures far above that in the ventricle. The heart does not provide pressure for extension of siphons or foot. Sea water pumped by isolated Tresus ventricles demonstrated that neither pericardium nor auricles are needed for ventricular filling, as had been hypothesized earlier. The morphology of the heart walls supports the concept of bivalve hearts as being a site of filtration, with the ventricle thought to play a larger role than the auricles. Valves in the heart and aortas which control direction of blood flow are described.
Automatic Activity of the Locomotor Centres of the Lumbar Cord in Lizards
Authors: Ten Cate J.
Published: April 2021

My previous experiments with salamanders (Triton cristatus;ten Cate, 1927) and tortoises (Testudo graeca;ten Cate, 1937) have shown that, after transection of the spinal cord in the thoracic region, locomotor movements of the hind limbs can be observed under favourable conditions while the front limbs remain motionless. These alternating movements are well co-ordinated but last only a short time; the front limbs then also begin to move.
The Function of A Heteromorph Antennule in A Spiny Lobster, Panulirus Argus*
Authors: Maynard D. M. , Cohen M. J.
Published: April 2021

The effects of electrical and mechanical stimulation upon a ‘naturally occurring ‘heteromorph appendage growing in place of one eyestalk in Panulirus argus were examined. The heteromorph resembled the outer flagellum of the antennule in form. Heteromorph stimulation elicited both a generalized withdrawal response, and a specific depression of the third segment and flagellum of the ipsilateral antennule. Such a depression response was also elicited upon stimulation of the ipsilateral outer flagellum of the normal antennule and by no other input investigated. The basic similarity of the two responses was confirmed by electromyography and by intracellular recordings from motor neurons and interneurons within the lobster brain. It was concluded that at least one afferent fibre component from the heteromorph and normal flagellum terminated upon the same interneuron pools, while avoiding others, and that consequently these observations provide evidence for the formation of functional inter-neuronal connexions according to type specificity.
Reflex Control of Abdominal Flexor Muscles in the Crayfish: I. The Twitch System
Authors: Kennedy Donald , Takeda Kimihisa
Published: April 2021

The polyneuronal innervation of crustacean muscles has been well explored in decapod limbs, both comparatively at the level of entire muscles (Wiersma & Ripley, 1952) and, by means of single motor axon stimulation and microelectrode recording, at the level of single muscle fibres (Fatt & Katz, 1953 a, b; Furshpan, 1955; Hoyle & Wiersma, 1958). Experiments of the latter sort have shown that motor axons produce excitatory junctional potentials (e.j.p.s) that may or may not give rise to active electrogenic events (spikes). The e.j.p.s evoked by different motor axons may differ in amplitude, rate of rise or fall, and tendency to facilitate upon repetitive stimulation; axons that evoke more sharply rising e.j.p.s exhibiting little facilitation have been termed ‘fast’, and others ‘slow.’
Electrical Activity in the Radial Nerve Cord and Ampullae of Sea Urchins*
Authors: Sandeman D. C.
Published: April 2021

A single shock applied through wick electrodes to the isolated radial nerve cord of a sea urchin produces a recordable potential in the cord. The potential is conducted along the cord at a velocity of between 14 and 20 cm./sec. The potential is complex and graded. Two components of the potential can be identified and have different thresholds to stimulation, conduction velocities and amplitudes. They are believed to represent two classes of fibres. The potential is conducted decrementally along the cord and normally cannot be recorded at distances greater than 60 mm. from the stimulus. The amplitude of the potential decays logarithmically falling to half after 7 mm. spread. There is no facilitation of amplitude or distance of spread. Potentials initiated simultaneously at either end of the isolated nerve cord collide and partially occlude each other. Stimulation of a side branch of the nerve cord evokes potentials recordable from only ipsilateral neighbouring side branches and the whole cord. However, contractions of the contralateral ampullae following stimulation of lateral branches reveal spread of the excitation beyond the region of recordable potentials. A single shock to a cord still attached to the test causes contraction of the associated ampullae. One ampulla will contract several times after a single shock, a period of relaxation following each contraction. Electrical activity recorded from the ampullae, and lasting many seconds after the single shock, corresponds with their contractions. The activity is believed to be muscle action potentials. Evidence of a feedback from damaged tube feet to the cord, suppressing ampulla response to cord stimulation, was found.
Studies on the Mode of Action of the Diapause Hormone in the Silkworm, Bombyx Mori L
Authors: Hasegawa Kinsaku , Yamashita Okitsugu
Published: April 2021

Glycogen synthesis in the ovary of Bombyx mori is accelerated by the diapause hormone. Such glycogen is derived, by way of the trehalose of the haemolymph, from carbohydrate in the fat body. Extirpation of the suboesophageal ganglion has the converse effect: a fall in glycogen in the ovary and an increase in blood trehalose and fat-body glycogen. Mobilization of fat-body glycogen is dependent on the presence of the ovaries, and of the suboesophageal ganglion. The same results can be obtained in male pupae after the implantation of ovaries. These observations on carbohydrate metabolism confirm the belief that the ‘target organ ‘of the diapause hormone is the ovary itself. The changes in other tissues are due to feedback.
Circulation in A Giant Earthworm,Glossoscolex Giganteus
Authors: Johansen Kjell , Martin Arthur W.
Published: April 2021

The annelid worms stand out among most other invertebrate forms by having a closed vascular system. Their blood usually contains haemoglobin in simple solution as a respiratory pigment. Some of the earthworms as a subdivision of this phylum may attain considerable size weighing more than 500–600 g., and may be as long as 120 cm. with a maximum diameter of 2–3 cm. It is surprising to find that the earthworm Glossoscolex giganteas of such great size has no special organs of respiration, the skin being the only surface available for gas exchange. Such a structural arrangement may depend upon specialized adaptations in the pattern of blood flow or in the respiratory characteristics of the blood, or both.
The Site and Permeability of the Filtration Locus in the Crayfish Antennal Gland*
Authors: Kirschner Leonard B. , Wagner Stanley
Published: April 2021

Inulin (MW 5000) and two dextrans (MW 15,000–20,000 and 60,000–90,000) appear in the urine of crayfish after injection into the blood. All three compounds are more concentrated in the urine than in blood, indicating that water is reabsorbed from a filtrate formed within the antennal gland. Inulin and the low molecular weight dextran seem to be handled in the same fashion since their urine/blood concentration ratios are about the same. However, the high-molecular-weight dextran is excreted only about 70% as effectively as the other pair. This suggests that filtration of polymers in the MW range 50,000-100,000 is restrained. Excretion of human serum albumin occurs but it is even more severely restricted than the large dextran. Mammalian globulin (MW about 180,000) and crayfish blood protein are not excreted in the urine. Blood protein becomes concentrated in the coelomosac. Localization of fluoescein-labelled mammalian globulin shows that the peritubular cells in the coelomosac are the main sites of protein accumulation. Concentration of blood protein in the coelomosac suggests that filtration occurs in this region, but the intracellular location suggests that the filtration mechanism differs from that in the vertebrate nephron.
The Effect of Photoperiod on the Developmental Rate of Drosophila Pupae
Authors: Harker Janet E.
Published: April 2021

The time taken for Drosophila melanogaster to complete three stages of pupal development has been measured for pupae entering each stage at each particular hour of the day in cycles of 12 hr. light: 12 hr. darkness, 4 hr. light:20 hr. darkness, 18 hr. light:6 hr. darkness. Similar measurements have been made for insects in which the larvae were subjected to the light cycles but the pupae remained in constant darkness. The duration of each stage is affected by the time of day, relative to the light cycle, at which the stage is entered. When pupae are in constant darkness the developmental rate of each stage is affected by the time of day at which the stage is entered relative to the particular light cycle to which the larval stage had been exposed. The eclosion rhythm, which arises as a summation effect of rhythms of development at earlier stages, may become bimodal in light cycles with suitable photofractions. The rate of development of a pupa entering a stage during the light period is related to the time-interval since the light-on signal ; the preceding dark period has no effect. The developmental rate of pupa entering a stage during the dark period is affected by the time-interval since the light-off signal, but may also be affected by the previous light-on signal although there is no simple relationship between them. As the developmental rates are maintained in constant darkness it is concluded that the rate of development is affected by factors following a diurnal rhythm. The form of the rhythm is determined by both light-on and light off signals, but the timing of the rhythm is determined by the two signals acting independently of each other.
Observations on the Absorption of Water, Diapause and Embryogenesis in the Eggs of the Cricket Teleogryllus Commodus (Walker)*
Authors: Browning T. O.
Published: April 2021

The eggs of Teleogryllus commodus absorb water only when the embryo has reached a particular stage of development. Water is absorbed just before the development of the embryo reaches the stage at which diapause occurs. Preventing the absorption of water prevents the further development of the embryo. These results are discussed in relation to other information on water absorption and diapause in the eggs of insects.
Pressure and Volume Relationships in the Ventricle, Conus and Arterial Arches of the Frog Heart
Authors: Shelton G. , Jones D. R.
Published: April 2021

Peak systolic pressures in the ventricle, conus and arterial arches differ by 1 or 2 mm. Hg only, and are reached at the same time. Pulse pressures are largest in the ventricle and smallest in the arterial arches, though their relationship to one another is variable and depends partly on heart rate. The conus continues to contract after relaxation of the ventricle. Blood flow from the heart occurs during four-fifths of the cardiac cycle and stops with the closure of the valves at the top of the conus. Volume changes in the conus are 5–10% of those seen in the ventricle. The conus is filled early in ventricular systole before the peak pressure is reached. The ventricle does 20 to 40 times more work than the conus in ejecting blood from the heart. The conus does not serve a depulsating function or make a major contribution to blood outflow from the heart in anurans.
The Physiology of Excretion in the Cotton Stainer, Dysdercus Fasciatus Signoret: II. Inorganic Excretion and Ionic Regulation
Authors: Berridge M. J.
Published: April 2021

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

Stimulation 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

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

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

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

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

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

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

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

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

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

Under 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

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

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

The 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

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

An 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

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

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

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

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.
Hormonal Control of Excretion in the American Cockroach
Authors: Mills Richard R.
Published: April 2021

When adult male cockroaches are deprived of water for 3 days the subsequent overcompensation of water ingestion causes the release of a diuretic hormone into the blood. Ligation experiments indicate that the hormone was released from the posterior part of the abdomen. The testing of various tissues extirpated from within this region revealed that only extracts of the terminal abdominal ganglion could promote diuresis. Homogenates of ganglia from normal animals fail to elicit the diuretic response ; this and other evidence suggests the presence of an antidiuretic hormone.