bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Evaporation of Water From Helix Aspersa
Authors: Machin John 
Published: April 2021

ABSTRACT
Observations of intact specimens of Helix aspersa together with experiments with isolated skin preparations are described. Under normal atmospheric conditions increases in haemocoelic pressure, probably due to general muscular activity, are sufficient to maintain the superficial mucous coating of the skin. Under conditions of rapid water loss more intense muscular undulations serve to spread mucus which collects in the grooves to more exposed areas of the skin. The water content, the rate of water loss in dry air, the equilibrium in saturated air and depression of freezing point of isolated mucus samples have been measured. The vapour pressure of mucus has been shown to be within 0-4% of that of distilled water under the same conditions. The significance of the above findings is discussed in relation to evaporative water loss and water uptake of an intact snail.
The Evaporation of Water From Helix Aspersa
Authors: Machin John 
Published: April 2021

ABSTRACT
The construction and use of a wind-tunnel apparatus is described in which measurements of evaporation under controlled conditions of temperature, humidity and air flow can be made. Two mathematical formulae, applicable to evaporation in relatively low wind speeds, are described. It is suggested that a promising approach to evaporation from moist-skinned animals is provided by the application of Leighly’s formula: where the rate of evaporation (E) is expressed in terms of the vapour pressure at the evaporating surface (p0) and in the ambient air (pd), the wind speed (ν) and the length of the evaporating surface parallel to the wind (x). The constant, K, is calculated independently and the terms n and c are left for empirical determination. Values of n and c for different types of evaporating surface are given together with the method used in their calculation. Those relating to flat evaporators and to the snail, Helix aspersa, are shown to differ significantly. In general n increases and c decreases as the amount of air disturbance caused by the snail increases. The fact that n for flat surfaces is in good agreement with previously established theory is taken as evidence that Leighly’s formula may be validly applied. The combined determination of n and c is introduced as a convenient assessment of a complex form in terms of air flow and evaporation.
Stretch Receptor Organs in Squilla Mantis Latr. (Crustacea: Stomatopoda)
Authors: Pilgrim R. L. C. 
Published: April 2021

ABSTRACT
Structures which have been described as muscle receptor organs were found to respond to experimentally applied stretch. The presence of both slowly-adapting and fast-adapting receptors was determined in those organs where two sensory cells and two receptor muscles have been described, i.e. in the abdomen and posterior four thoracic segments. In the fourth thoracic segment, with two cells on a single receptor muscle, one organ is slowly-adapting and the other fast-adapting, with properties not distinguishable from those where separate receptor muscles are present. In the third thoracic segment, with a single cell and receptor muscle, the organ is slowly-adapting. In the second thoracic segment a slowly-adapting cell was discovered. It is without a receptor muscle or accessory innervation and resembles an N-cell of the Decapoda. The reactions of the abdominal organs to acetylcholine and to y-amino butyric acid are qualitatively similar to those in Decapoda. The series of stretch-sensitive organs in Squilla and in Decapoda are compared. The evidence supports the hypothesis that there was, in the trunk of the primitive Malacostraca, a segmentally arranged series of slowly-adapting and fast-adapting receptor organs, that anatomical simplification of the anterior organs has occurred progressively with the development of the carapace and that N-cells are derived from the slowly-adapting type.
Co-Ordination of Successive Activities in An Aphid. Depression of Settling After Flight
Authors: Kennedy J. S. , Booth C. O. 
Published: April 2021

ABSTRACT
Flight has a cumulative ‘priming’ effect (excitatory after-effect) on the settling responses of an aphid landing on a surface, even when the flight has been interrupted by one or more previous landings. But when the bouts of flying between landings were kept brief (1 min.) there was also an opposite, depressing or inhibitory aftereffect on settling which reduced and in certain conditions regularly outweighed the priming effect. Which of the two after-effects predominated depended on the kind of surface landed on each time, on the strength of the settling responses at previous landings and on the total time the aphid had been flying. The depressing effect as measured on a standard host leaf was negligible when the flight had been interrupted by landings on a card, where the settling responses were weakest and soonest inhibited by flight again, greater after landings on a no host leaf and greatest after landings on the host leaf, itself where settling responses were strongest. When two successive landings were both made on the same surface, a depression of settling at the second landing was more likely after a strong previous settling response than after a weak one; it was also more likely when the two landings were made on a non-host than when they were made on a host. Flight and settling are nervous antagonists and the terms ‘antagonistic induction’ and ‘antagonistic depression’ are applied, respectively, to the excitatory and the inhibitory after-effects of flight on settling. These are components in the co-ordination of flight and settling as successive activities and do not necessarily describe the sequences observed.
Studies on the Mode of Action of the Diapause Hormone in the Silkworm, Bombyx Mori L
Authors: Hasegawa Kinsaku 
Published: April 2021

ABSTRACT
The susceptibility of ‘non-diapause’ pupae to diapause hormone, the sexual difference in production of diapause hormone in the suboesophageal ganglion (SG), the changes in diapause hormone content of the SG during larval-pupal-adult development, and the hormone production in polyvoltine race, were studied by injecting diapause hormone extracts into pupae expected to produce non-diapause eggs. The susceptibility of ‘non-diapause’ pupae of a bivoltine race (Daizo) was very low, or the hormone injected was almost inactivated. The susceptibility of ‘nondiapause’ race to diapause hormone is different in different races. As for sexual differences in content of diapause hormone in moth heads, males are superior to females, which was further substantiated by injecting extracts from the SG of both sexes. From the activity of diapause hormone extracts derived from larval, pupal and adult SG, the hormone production in SG is raised during the late pupal stage, especially in males. It is also observed that larval SG produces the hormone, and the hormone production in the SG of male moths after mating becomes weak. Male moth heads of ‘non-diapause’ worms (polyvoltine race), as well as of ‘diapause ‘worms, contain diapause hormone ; though activity is less than in ‘diapause ‘worms, which reflects the occurrence of diapause eggs caused by SG-transplantation. It is highly probable that the bioassay by injecting diapause hormone extracts reveals the activity of the SG in the silkworm. The activity of the SG in the polyvoltine race has been discussed from the standpoint of diapause determination in the silkworm.
The Distribution and Exchange of Inorganic Ions in the Central Nervous System of the Stick Insect Carausius Morosus
Authors: Treherne J. E. 
Published: April 2021

ABSTRACT
The distribution and exchange of inorganic ions between the central and the haemolymph has been studied in the stick insect, Carausius morosus, by flame photometry and radioactive tracers. The exchanges of labelled ions show rapid and slow components which correspond to extracellular and intracellular compartments within the central nervous system. The uptake of sodium from the haemolymph and its concentration in the extracellular fluid is reduced in the presence of metabolic inhibitors. The distribution between haemolymph and extracellular fluid of calcium and magnesium, and also of sodium in poisoned preparations, conforms to a Donnan equilibrium. The distribution of potassium, even in poisoned preparations, does not conform and it is suggested that the activity of this ion may be lower than in free solution. The concentration of magnesium is appreciably greater in the extracellular than in the intracellular compartment. The possible role of magnesium in nervous transmission in this insect is discussed.
Micropuncture Studies of the Concentrations of Sodium, Potassium and Inulin in the Crayfish Antennal Gland
Authors: Riegel J. A. 
Published: April 2021

ABSTRACT
The concentrations of sodium, potassium and inulin in the blood and urine have been measured at various sites in the antennal gland of Orconectes limosus and Austropotamobius pallipes pallipes. The sodium concentration in all parts of the antennal gland is less than the sodium concentration in the blood. Only in the bladder is the sodium concentration significantly different from the sodium concentration in the other parts. The potassium concentration in all parts of the antennal gland, except the bladder, is greater than the potassium concentration in the blood. The potassium concentration within the bladder is much less than that in the blood. The U/B ratio for inulin exceeds one in all parts of the antennal gland. These results are discussed in relation to the function of various parts of the antennal gland and to the manner in which urine is formed by the crayfish antennal gland.
Sodium Balance in the Freshwater Prawn, Palaemonetes Antennarius
Authors: Parry Gwyneth , Potts W. T. W. 
Published: April 2021

ABSTRACT
The sodium content of the freshwater prawn Palaemonetes antennarius and the rates of influx and efflux of sodium in fresh water and a variety of other media are described. The greater part of the influxes in all media is due to active uptake. The relationship between active uptake and the external and internal concentrations is described and it is concluded that the animal is living close to its viable limits of dilution. The greater part of the efllux in fresh water is due to loss in the urine.
On The Initiation of Spermatophore Formation in the African Migratory Locust, Locusta Migratoria Migratorioides Reiche and Fairmaire
Authors: Gregory G. E. 
Published: April 2021

ABSTRACT
The behaviour of the male culminating in spermatophore formation is divisible into four phases: approach; mounting; copulation; and spermatophore formation. All appear to be controlled and co-ordinated solely through the nervous system. The initiation of sexual behaviour requires the brain and one or more of the receptor-bearing head structures (antennae, palpi and eyes) to be functional. Approach and mounting behaviour involves the receptors, nervous system and effectors of the head and thorax only. Copulation is controlled through the ganglia of the abdomen but for its initiation these ganglia have to be in nervous communication with a centre anterior to them. Also both cerci must be functional. Spermatophore formation is initiated, and its early stages are controlled, by an anterior centre which has its effect through the last abdominal ganglion. The later stages of formation, appear to be controlled by the last abdominal ganglion alone. The presence of the female is essential for the initiation and early stages of spermatophore formation, but her role during the later stages of the process appears to be a completely passive one.
The Fate of Thorium Dioxide Injected Into the Pedal Sinus of Bullia (Gastropoda: Prosobranchiata)
Authors: Brown A. C. , Brown Rosalind J. 
Published: April 2021

ABSTRACT
The removal and ultimate disposal of foreign particles injected into the haemolymph of the sandy-beach snail, Bullia, has been studied by using the radio-opaque dye Thorotrast. Particles are removed by phagocytic haemocytes which migrate by various routes to the outside of the body. The main pathway is through the heart wall into the pericardial cavity and via the renopericardial canal into the lumen of the kidney, from which the cells escape into the mantle cavity. The injection of foreign particles stimulates a marked increase in the haemocyte population and also in the mitotic index. The final discussion integrates the available evidence and a comparison is made between Bullia and other molluscs. The origin of the macrophages is discussed.
Joint Receptors in the Antennule of Panulirus Argus Latreille
Authors: Wyse Gordon A. , Maynard Donald M. 
Published: April 2021

ABSTRACT
A single elastic strand organ, presumably a chordotonal proprioceptor, occurs at each of the three distal joints of the antennule in Panulirus argus. These organs are essentially identical with those described at the joints of the pareiopods. Movement at the second and third joints is along one dorso-ventral axis. Unidirectional movement and position receptors responding to flexion and extension occur at both joints. Movement at the first joint is biaxial, either dorso-ventral or medio-lateral. Many unidirectional movement and position receptors are non-specific to axis, and respond to flexion along both axes or to extension along both axes. In addition, some completely specific position and movement receptors occur that respond to extension or to flexion only along one axis. No bi-directional axis-specific receptors were found. Accessory strands act in conjunction with the main elastic strand during joint movement to produce differential stretch according to direction or axis of movement. It is suggested that such differential mechanical distortion is responsible for the part receptor specificity observed.
Ciliary Activity and Oxygen Uptake in Branchiostoma Lanceolatum (Pallas)
Authors: Courtney W. A. M. , Newell R. C. 
Published: April 2021

ABSTRACT
The rate of oxygen uptake by single specimens of Branchiostoma lanceolatum has been shown to vary considerably. Some animals in sealed vessels at 15 ° C. were able to utilize the oxygen linearly down to less than 20% of air saturation. Others ceased to absorb oxygen at high saturations while yet others displayed two different rates in a sequence starting initially with a high rate. There are three possible rates of oxygen utilization, as well as a zero rate, for an animal at any temperature between 10 and 19 ° C. Animals in gravel exhibit only two rates at lower temperatures. The slowest rate varies exponentially with temperature but the two faster rates show a rapid increase between 10 and 15 ° C. with little change outside this temperature range. The effect of size and temperature on the increased oxygen uptake during the faster rates of respiration are discussed. It is suggested that ciliary activity of the pharynx could be associated with the extra oxygen utilization. It has been found that there are three inhalant stream velocities, a fast, a slow and a zero rate with no intermediate rates. Study of the isolated portions of the pharyngeal wall confirm that the fast inhalant current is set by the activity of all the cilia to give a feeding stream. The slow stream is set up by the lateral cilia, which continue to beat when the frontal cilia and most of the lateral cilia have been inhibited by lowered oxygen concentrations. The lateral cilia have been shown to be under nervous control and to be inhibited by pressure on the pharyngeal bars. This mechanism depends on the presence of a connexion between the pharyngeal bars and the endostyle.
The Signal Generated by An Insect in A Spider’s Web
Authors: Parry D. A. 
Published: April 2021

ABSTRACT
There is evidence that web-spinning spiders discriminate between prey and artifacts in their webs, and that the signal involved is a mechanical one. As a con tribution to our understanding of the basis of this discrimination, an analysis has been made of the natural signal generated by an insect in the web of the British house spider Tegenaria atrica. The signal investigated was frequency-limited to 1 kc./sec., this being the upper limit of the linear response of the specially designed transducer. The signal has an irregular wave-form with most of the energy lying below 50 cyc./sec. Damped transverse and rotational oscillations of the mass of the spider in the compliance of the web have been recognized. In addition there are ‘fast transients ‘, most likely due to the sudden release of tension in the web by slight movements of the insect. The possibility that the fast transients form the basis of prey-recognition is being investigated.
Osmotic and Ionic Regulation in the Prosobranch Gastropod Mollusc, Viviparus Viviparus Linn
Authors: Little C. 
Published: April 2021

ABSTRACT
Investigations of the composition of the blood and tissues of freshwater invertebrates, and the relations that these bear to the composition of the external medium, have in the main been confined to crustaceans and insect larvae, whilst the molluscs have been somewhat neglected. Potts (1954, 1958) and Florkin & Duchâteau (1950a) have studied the lamellibranch Anodonta cygnaea in some detail. Duval & Portier (1927) and Florkin & Duchâteau (1950b) have given some figures for the pulmonate Limnaea stagnate. Among the prosobranchs, published work appears to provide nothing more than values for the depression of freezing-point of the blood of Viviparus viviparus (Fredericq, 1904), V. fasciatus (Obuchowicz, 1958), and Theodoxus fluviatilis (Neumann, 1960).
Nerve Impulse Patterns and Reflex Control in the Motor System of the Crayfish Claw
Authors: Wilson D. M. , Davis W. J. 
Published: April 2021

ABSTRACT
The opener muscle of the crayfish claw receives, under nearly natural conditions, a train of excitatory nerve impulses which may show a temporal patterning to which the muscle is specially sensitive. Especially at high frequencies the impulse train contains doublets which form a separate class in the interval distribution. Their appearance at high frequencies gives rise to an increase in the coefficient of variation of interval lengths. Excitatory and inhibitory motor neurons to the same opener muscle seem to be part of the same commonly excited motor neuron pool. Frequency changes in the two axons generally show positive correlations. For most inputs and for ‘spontaneous’ central drive the excitor has the lowest threshold and shortest latency, and it gives the earliest indication of changes of excitatory state. Proprioceptive input from the claw may excite both motor neurons, but generally the inhibitory one gives the earlier, bigger response. The peripheral inhibition completes a negative feedback loop. Inhibitory frequencies plotted against concurrent excitatory frequencies give points falling into two groups with different slopes dependent upon input source. For general body inputs the slope is less than one and for proprioceptive claw input it is much more than one. This divergence leads to greater effectiveness of either excitation or inhibition as overall level of output increases, with a good separation of antagonistic functions in spite of the apparent lack of reciprocal interaction.
Reflex Control of Abdominal Flexor Muscles in the Crayfish
Authors: Kennedy Donald , Takeda Kimihisa 
Published: April 2021

ABSTRACT
In the crayfish abdomen most of the power for the flexor twitches employed in swimming is supplied by the massive oblique muscles which are innervated by large motor axons from the third root. All of the delicate flexor control of the abdomen is vested in a thin, superficial sheet of muscle fibres which have the histological characteristics of ‘slow’ muscle and are innervated by a special, independent supply of small motor nerves (Kennedy & Takeda, 1965). These forty or so muscle fibres and half-dozen axons comprise a reflex apparatus of exquisite complexity, both with respect to innervation pattern (which ranges from single to sextuple for single muscle fibres) and to central modulation of efferent discharge.
Multiple Pacemakers and the Behaviour of the HydroidTubularia
Authors: Josephson R. K. , Mackie G. O. 
Published: April 2021

ABSTRACTThe spontaneous behaviour of the hydroid Tubularia results from the activity of a number of pacemaker systems in the polyp, there being a major pacemaker system in the distal stalk (the NP system), another in the hydranth body (the HP system) and individual pacemakers in each of the tentacles. The NP system produces single electrical pulses and bursts of three or more pulses, the HP system itself produces single pulses and short bursts of 2-4 pulses, and the tentacle pacemakers fire irregularly. The HP and NP systems are mutually interactive. When the NP system fires in a burst it usually drives the HP system to fire concurrently. Single firing by the NP system sometimes triggers the HP system to fire, and single HP firing can trigger the NP system. Single HP firing is most likely to trigger the NP system if it comes long after the last NP firing, i.e. late in the NP spontaneous cycle. When the HP system independently fires a burst or is driven by the NP system to fire a burst, it drives pacemaker systems in the proximal tentacles to fire concurrently. Firing of the HP system is associated with a behavioural response termed a concert. During a concert the proximal and sometimes the distal tentacles are synchronously elevated. During the longer NP-HP bursts the neck contracts. A peristaltic wave sweeps down the proboscis following the tentacle elevation. Concerts without neck contraction result in mixing of fluid in the enteron chamber of the proboscis ; concerts with neck contraction result in tidal exchange of fluid between the neck chamber and the proboscis chamber. Stimulation of the conducting system in the stalk termed the triggering system (TS) can trigger the NP system to fire. A stalk stimulus is most likely to trigger the NP system if it comes within a few seconds of NP firing, i.e. early in the NP spontaneous cycle. Firing of the NP system of one polyp in a colony can trigger the NP systems of connected polyps. Interpolyp triggering is probably mediated through the TS conducting system. The coupling between NP systems of connected polyps results in synchronization of NP bursts throughout a colony. Because of the coupling between NP and HP systems within single polyps the longer HP bursts, which are those occurring when the HP system is driven by the NP system, are also usually synchronous in connected polyps. This results in concerts with neck contraction being nearly synchronous throughout a colony. Such synchronization facilitates transfer of fluid between the two enteron chambers of polyps during concerts. Prolonged, low-frequency stalk stimulation inhibits spontaneous activity of a polyp, the inhibition increasing with increasing stimulus frequency. The large size of the spontaneous electrical pulses suggests that they are not the result of nervous activity, but possibly due to activity of more primitive co-ordinating mechanisms.