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

ABSTRACT
Air flow and the water-vapour gradient over a freely evaporating surface is described, and the concept of boundary-layer thickness which expresses such a gradient is introduced. A direct method of estimating boundary-layer thickness by means of a hot-wire anemometer is described. Comparison of observed and effective boundary-layer thickness, calculated from evaporation data, have suggested that the gradient of water vapour is steeper than aerodynamic measurements indicate. An empirical relationship between aerodynamic and vapour boundary layers has been obtained for a two-dimensional evaporator and for the snail, Helix aspersa, and a new evaporation formula derived. Evidence for supposing that aerodynamic and vapour boundary layers do not coincide unless the evaporating surface is greater than 22 cm. in length is presented. Possible errors in the estimation of boundary-layer thickness when air flow is interrupted by the snail’s shell are considered. The importance of differences in air flow produced by placing the animal in different positions relative to the wind is discussed.
The Effect of Some Anions and Cations Upon the Fluxes and Net Uptake of Sodium in the Larva of Aedes Aegypti (L)
Authors: Stobbart R. H. 
Published: April 2021

ABSTRACT
Starved 4th-instar larvae of Aëdes aegypti, when put into deionized water at a density of ten larvae/zoml., are able to achieve sodium balance at the low external concentration of 5µM Na/1. The balancing process involves a 10% drop in total sodium content, a more or less complete activation of the mechanism for sodium transport, and a reduction in the permeability of the larva to sodium as measured by the net sodium loss into deionized water. It is very probable that most of this reduction occurs in the anal papillae. The relationship between external sodium concentration and sodium influx in larvae previously ‘balanced’ in deionized water is described approximately by the Michaelis equation. The sodium outflux also increases with increasing external sodium concentrations. The net uptake of sodium by ‘balanced larvae’ appears to be significantly greater from solutions of NaCl than from solutions of NaNO3, NaHCO3, and NajSO22. The ions K+ Ca++ Mg++ and NH224 when present as chlorides stimulate the influx of sodium from o-i mM/1. sodium chloride. When present as nitrates or sulphates they either have no effect or cause an inhibition of influx. The results in 4 and 5 suggest that movements of chloride may be important in sodium uptake, and chloride uptake has been found to occur independently of sodium uptake. Measurements of potential difference between haemolymph and medium demonstrate active transport of both sodium and chloride.
The Vertical Lobe and Touch Learning in the Octopus
Authors: Wells M. J. 
Published: April 2021

ABSTRACT
The vertical lobe is the topmost part of the brain of a cephalopod. It is the largest of a series of lobes, characterized by small cells and a dense neuropil, overlying parts of the supraoesophageal brain concerned with higher motor control. Because of its position it is easy to remove surgically.
The Role of Certain Optomotor Reactions in Regulating Stability in the Rolling Plane During Flight in the Desert Locust, Schistocerca Gregaria
Authors: Goodman Lesley J. 
Published: April 2021

ABSTRACT
It has been suggested by several authors that optomotor responses play a part in promoting stability in flying insects (Pringle, 1957). Faust (1952) examined a variety of insects and found only the Diptera and Odonata amongst them to be fully stable in complete darkness, and experiments with blind flies having only one haltere led him to suggest that visual regulation might play some part in regulating stability in the rolling plane in Calliphora. Von Buddenbrock (1937) described a ‘Lichtruckenreaction’ in which insects orientated themselves so that the greater light intensity fell on a given region of the eye, generally the dorsal region, and which appeared to play a large part in maintaining stability in the rolling plane. Mittlestaedt (1950) analysed this reaction in greater detail in the dragonfly, Anax imperator. He showed that, when the movements of a flying dragonfly were restricted to the rolling plane, it rotated the head until the uppermost region of the eyes was maximally stimulated and then aligned the body with the head by means of proprioceptive hair plates in the neck region. The inertia of the wide, heavy head appears to give the dragonfly a dynamic sense which preserves its stability in complete darkness. In other cases visual stimuli appear to influence stability by a direct effect on the thoracic motor pattern rather than having an indirect effect through head movements (Pringle, 1957).
Osmotic Regulation in the Tadpoles of the Crab-Eating Frog (Rana Cancrivora)
Authors: Gordon Malcolm S. , Tucker Vance A. 
Published: April 2021

ABSTRACT
Salinity tolerance, osmoregulatory mechanisms and some effects of salinity on embryonic development and metamorphosis have been studied in the tadpoles of the euryhaline crab-eating frog (Rana cancrivora). Tadpoles in developmental stages III-XIX survive well in all salinities from fresh water to 32% sea water. They are good osmoregulators over this entire range, plasma osmotic concentration changing by only 250 m-osmoles/1. in the face of environmental concentration changes of 900 m-osmoles/1. Na, Cl, and K account for over 90% of plasma osmotic concentration in all external concentrations. The osmoregulatory mechanisms used by the tadpoles appear to be similar to those used by euryhaline teleost fishes. In hyperosmotic media they probably drink, then excrete salts by an extrarenal pathway. A metamorphosis in osmoregulatory mechanisms occurs simultaneously with morphological metamorphosis. The osmoconforming behaviour of adult frogs is fully developed in the tadpoles by developmental stage XXV. As in other anuran species there probably is no significant urea production before metamorphosis. Both early embryonic development and the completion of metamorphosis beyond stage XIX apparently require low salinities. The pattern of osmoregulation shown by tadpoles of the freshwater R. limno-charis is identical with osmoregulatory patterns found in adult freshwater anurans. Evolutionary and ecological impheations of the data are discussed.
The Spectral Sensitivity of the Goldfish and the Clawed Toad Tadpole Under Photopic Conditions*
Authors: Cronly-Dillon J. R. , Muntz W. R. A. 
Published: April 2021

ABSTRACT
The visual pigments of the vertebrate retina fall into two major classes, depending on whether they are based on vitamin A1 or vitamin A2. The rod pigment in the former case is rhodopsin, and in the latter case porphyropsin, and the scotopic sensitivities of the animals agree well with the absorption spectra of the relevant pigment. Later work led to the view that the photopic sensitivities of animals also fall into the same two classes: those animals with visual pigments based on vitamin A1 are maximally sensitive at about 560 mμ, and those with pigments based on vitamin A2 at about 620 mμ (Granit, 1941, 1947). The first type of photopic sensitivity can be roughly fitted by the absorption spectrum of the pigment iodopsin, the second by the absorption spectrum of the pigment cyanopsin (Wald, Brown & Smith, 1953, 1955). The difference between the rods and cones within each group is due to the opsin part of the molecule.
Neuronal Mechanisms Underlying Control of Sound Production in A Cricket: Acheta Domesticus*
Authors: Ewing Arthur , Hoyle Graham 
Published: April 2021

ABSTRACT
Analyses of neuronal mechanisms underlying instinctive behaviour have long been required (Tinbergen, 1951) but have not been forthcoming. The reason seems to lie in part in a lack of agreement as to suitable experimental animals. There are now signs that certain large insects, which are available in many laboratories, and whose nervous systems are amenable to electrophysiological investigation, have been selected as first-choice subjects for detailed investigations. As examples we may refer to the work of Wilson (1961, 1964) on locust flight mechanisms, Roeder, Tozian & Weiant (1961) on the praying mantis and Hoyle (1964) on general locomotory activity in locusts.
The Formation of Urine by the Prosobranch Gastropod Mollusc Viviparus Viviparus Linn
Authors: Little C. 
Published: April 2021

ABSTRACT
In all aquatic molluscs examined (Anodonta—Picken, 1937; Haliotis—Harrison, 1962; Octopus—Potts & Martin, 1963), blood is filtered through the wall of the heart (or branchial heart appendages in Octopus) into the pericardium. The pericardial fluid passes to the kidney, where secretion and reabsorption modify it to form the final urine. In the terrestrial pulmonates, however (Achatina—Martin, Harrison & Stewart, 1953; Helix pomatia and Archachatina—Vorvohl, 1961), blood appears to be filtered directly into the kidney, and reabsorption takes place in the ureter. In the present paper the inorganic composition of the urine of the freshwater prosobranch Viviparus viviparas is analysed and the rate of urine production is measured. The mechanism of urine formation is then examined in some detail.
The Occurrence and Functional Characteristics of Heteromorph Antennules in An Experimental Population of Spiny Lobsters, Panulirus Argus*
Authors: Maynard D. M. 
Published: April 2021

ABSTRACT
Eyestalks were removed unilaterally from forty-nine Panulirus argus. Twenty-three of the forty-three animals remaining alive to the first moult regenerated a heteromorph antennular outer flagellum in place of the amputated eye. None of the lobsters moulting within less than 3 months of eyestalk ablation regenerated a heteromorph; 70% of those moulting after more than three months recovery regenerated a heteromorph. If the heteromorph did not appear upon the first moult it usually continued to be missing after the second or third moult. Mechanical stimulation of the heteromorph produced a general withdrawal reaction in all lobsters tested, and in most either a specific cleaning reflex directed toward the stimulated heteromorph, or a specific movement of the normal ipsilateral antennule, or both. The withdrawal and antennular movement, when it occurred, resembled responses elicited via stimulation of the normal antennular flagellum. Behavioural responses were followed in a selected subpopulation for periods ranging from one to nearly two years, and over one or two moults. No significant changes in behavioural responses to heteromorph stimulation were detected within that time. The conduction-velocity spectrum of fibres in the heteromorph nerve resembled that in the outer flagellar branch of the normal antennule nerve in having both a fast and a slow component. However, the velocity of the fast component of the heteromorph nerve was often less than normal for the flagellar branch of the antennule nerve, and additional components of intermediate velocity occurred in some animals. According to the direction or nature of the mechanical stimulus both heteromorph and normal flagella elicited inhibitory and excitatory responses in the nerve to the depressor muscle of the outer flagellum of the normal ipsilateral antennule. Responses of the flagellar depressor muscle of the ipsilateral antennule to electrical stimulation of the heteromorph varied among individuals, but in general resembled later components of the response to similar stimulation of the normal antennular flagellum. It is tentatively concluded that at least some of the heteromorph afferents make specific central connexions on neuron pools normally associated with antennular flagellum afferents. The difficulties of drawing such inferences from indirect observation are indicated.
Anelasticity in Bone and Echinoderm Skeletons
Authors: Currey J. D. 
Published: April 2021

ABSTRACT
Bones and echinoderm skeletons have been tested for anelasticity. Bone shows considerable, largely anelastic strains, continuing for at least 54 days, by which time the extra deflexion may be 130% of the original deflexion. The rate at which the anelastic deflexion appears is proportional to the applied stress. Between 2 and 50° C. there is a 300% increase in the rate at which anelastic deflexions in bones appear. Drying seems not to affect irreversibly the anelastic properties of bone. Echinoderm spines show no anelastic deflexion on prolonged loading. The mechanical behaviour of the skeletal materials of the two phyla investigated are such as would be expected from their constitution. The biological significance of these findings is discussed. It is concluded that anelasticity will, except perhaps in a few special cases, be of only marginal importance in vertebrates in life. The adaptive significance of the difference between bone and the skeletal tissue of echinoderms is as yet unknown. It does not lie in their anelastic properties.
Haemolymph Proteins and Yolk Formation in Rhodnius Prolixus Stål
Authors: Coles G. C. 
Published: April 2021

ABSTRACT
There are two adult-specific proteins in the haemolymph of Rhodnius. They appear to be formed in the fat body. The two proteins are absorbed by the oocytes and form the bulk of the soluble egg proteins. The changes in the concentration of total protein in the haemolymph and of four protein fractions, as separated on cellulose acetate, do not reflect egg production. This may be a consequence of the hormonal control of reproduction.
Nerve Pathways and Reflex Siphon Withdrawal in the Surf Clam
Authors: Mellon Deforest 
Published: April 2021

ABSTRACT
Neural pathways controlling reflex withdrawal of the siphons have been examined in the surf clam. Conduction-velocity measurements, coupled with intracellular recordings of postsynaptic responses, indicate that the pathways involved are among the fastest in the relevant nerve trunks. Cell bodies of neurons in the efferent limb of the reflex are located in specific paired regions of the visceral ganglion. Their axons are distributed to ipsilateral effectors via branches of the posterior pallial nerve and input to these cells is derived from a wide area of the periphery involving both sides of the animal. This pronounced sensory convergence can adequately account for symmetrical siphon withdrawal. It is concluded from several lines of evidence that fast reflex pathways within the ganglion are monosynaptic in nature. In addition, the prolonged time course of the postsynaptic response to single volleys, and the capabilities of the synaptic contacts for spatial and temporal summation, make it possible to account for after discharges in the efferent pathways lasting a second or more. Prolonged activity from these cells has not been observed in isolated visceral ganglion preparations, and it is possible that the sustained closure is controlled by pathways involving different groups of neurons.
The Physiology of Excretion in the Cotton Stainer, Dysdercus Fasciatus Signoret
Authors: Berridge M. J. 
Published: April 2021

ABSTRACT
The intestine of Dysdercus is discontinuous in the larval instars, and urine from the Malpighian tubules is therefore uncontaminated by gut contents. Excretion has been studied during the fifth instar, which lasts 8 days. Feeding only occurs in the first 4 days, during which there is a marked fall in water content. In the last part of the instar, when the animal only drinks, the water content returns to its original level. The urine of Dysdercus is always liquid. There is a rapid rate of excretion during the first half of the instar, but when feeding ceases there is no further micturition and urine is retained in the rectum. Therefore there are two phases of excretion, designated excretory and post-excretory phases respectively. The rectal epithelium is incapable of reabsorbing water against an osmotic gradient. The urine which is retained in the rectum during the post-excretory phase acts as a water store ; evaporative water loss is balanced by withdrawing water from this reservoir. During the excretory phase, a large volume of liquid is lost via the excretory system, but the loss is made good by drinking.
Some Experiments on the Chemotactile Sense of Octopuses
Authors: Wells M. J. , Freeman N. H. , Ashburner M. 
Published: April 2021

ABSTRACT
A method of training octopuses to make chemotactile discriminations is described. The animals can readily be taught to distinguish between porous objects soaked in sea water and similar objects soaked in sea water with M/10 KC1 added. Using pairs of objects soaked in solutions with different amounts of KC1 added, minimum distinguishable concentrations were determined over the range M/10−M/100. Effective discrimination broke down when the ratio of the two test concentrations was of the order of 1·3. This approximates to the values found in chemical discrimination experiments with mammals and insects. Attempts were made to determine the minimum detectable concentration of added KC1 by progressive dilution of the M/10 KC1 solution used in the initial training. Additions to sea water down to M/105 were distinguished and there was some indication that octopuses can, in fact, detect added KC1 at much smaller concentrations; the addition of M/1010 KC1 produced a significant decline in the ability of animals under training to discriminate between M/106 KC1 and sea water. Experiments on acid discrimination indicated that acids were distinguished on a basis of their pH, with acetic tasting noticeably more acid than HC1 or H2SO4 at the same pH. Again, the results closely parallel those that have been obtained with mammals and insects.
Influence of Previous Preferences on the Memory of Octopus Vulgaris After Removal of the Vertical Lobe
Authors: Young J. Z. 
Published: April 2021

ABSTRACT
Octopuses from which the vertical lobe had been removed attacked a vertical rectangle more readily than a horizontal one when both shapes were moved vertically. During discrimination training the results differed markedly according to which figure was rewarded with food. When a vertical rectangle was positive the excess of attacks at this figure increased both within and between sessions, the animals showing considerable ability to learn. When a horizontal rectangle was the positive figure the responses to it were at first ‘paradoxical’, the negative shape being attacked more often. There was then improvement within each session, but little if any between the sessions. Octopuses without the vertical lobe quickly ceased to attack crabs shown at 4 min. intervals when shocks were given for attacks, and the effect could still be detected 4 hr. later. When crabs were shown at 8 min. intervals, and shocks given for attacks, there was no decline in attacks over fourteen trials. Fifteen hours later, however, some residual signs of the shocks were evident when trials were resumed at 8 min. intervals. Although all of the animals at first attacked they soon stopped doing so. After a further 15 hr. all attacked again but soon ceased to do so after receiving shocks. Normal animals, by contrast, all ceased to attack the crabs shown at 8 min. intervals after receiving four or five shocks. The memory is much more retentive in normal animals, so that 2 days after receiving shocks the octopuses seldom attacked the crabs.
Directional Sensitivity of the Ears of Noctuid Moths
Authors: Payne R. S. , Roeder K. D. , Wallman J. 
Published: April 2021

ABSTRACT
Noctuid moths of several species were mounted at the tip of a tower of fine tubing in acoustic ‘free space ‘. Recordings were made of the intensity of a brief pulse of ultrasound necessary to produce a constant tympanic nerve response for any angle of sound presentation relative to the moth’s body axis. Such plots of intensity versus angle were made with the wings held in several postures approximating those assumed in normal flight. The data indicate that sound intensity reaching the tympanic organ can vary by as much as 40 db. depending upon: (a) the position of a sound source relative to the moth’s body axis, and (b) the position of its wings. With wings above the horizontal plane each ear reports sounds c. 20-40 db. louder on the ipsilateral side than on the contralateral side. With wings below the horizontal, the lateral asymmetries are replaced by a dorsoventral asymmetry in which each ear reports sounds coming from below the body c. 10-25 db. louder than sounds coming from above. Directional sensitivity plots at 60 kcyc./sec. are more complex than plots at 30 kcyc./sec.—as expected. A theory is presented to explain how a moth could determine the direction of a sound source in three-dimensional space by comparing the intensity reports of both tympanic organs during a complete wing cycle.
An Automatic Diver Balance
Authors: Larsson Sune , Løvtrup Søren 
Published: April 2021

ABSTRACT
An automatic, electromagnetic diver balance is described. The working principle of this instrument is that a small plastic cylinder, the diver, with density less than one is kept floating in an aqueous medium by a magnetic force acting on a permanent magnet enclosed in the diver. In the floating position the diver cuts off a light beam which, through an electronic system, controls the magnetic force acting upon the diver. The latter will move down until its buoyancy is compensated by this force. With this balance one may register the submerged—or reduced—weight of any object placed on the floating diver. The apparatus has hitherto found application in water-permeation studies (D2O-H2O exchange) and in determinations of the cortical tension in the frog’s egg. Potentially the instrument may be used for various other purposes, notably for manometric determinations. Miss Rita Gustafson, Mrs Margareta Jaksch, and Mrs Inger Janson have done all the practical work associated with testing out the method, their excellent assistance is gratefully acknowledged. The work has been supported by grants from Natur-vetenskapliga Forskningsrådet.
Nervous Control of the Mechanical Properties of the Abdominal Wall at Feeding in Rhodnius
Authors: Maddrell S. H. P. 
Published: April 2021

ABSTRACT
When larvae of Rhodnius feed, the abdominal wall rapidly becomes extensible. This change is brought about peripherally by the abdominal nervous supply; as a consequence, abdominal segments which have been denervated fail to stretch as much at feeding as do neighbouring innervated segments. The stimulus for this change originates in the head. It appears that the sensations accompanying feeding are responsible and that they have a cumulative effect, so that the degree of plasticization of the abdominal wall depends on the length of time during which the insect has been sucking. Neurosecretory axons are the only known efferent supply to the abdominal wall and so it is most probable that they cause the localized plasticization. The evidence suggests that the plasticization of the abdominal cuticle is a result of an increase in its water content. The increase in plasticity of the abdominal wall is temporary, the effect decreasing progressively after feeding.