bluuebunny/crossref_metadata_2025 huggingface dataset:
A Study on the Fibre Diameter and Certain Enzyme Concentrations in the Flight Muscles of Some Butterflies
Authors: George J. C. , Bhakthan N. M. G.
Published: April 2021

Fibre diameter and enzyme content were studied in the flight muscles of butterflies exhibiting various capacities for flight. The flight muscles of the better fliers are composed of narrow fibres, while those of the poor fliers are composed of larger fibres. The fibres in any one muscle are uniform with regard to the size and the content of a few enzymes studied, viz. lipase, acid and alkaline phosphatases, ATPase and succinic dehydrogenase. Quantitative estimation of the lipase activity in the flight muscles of different butterflies showed a remarkable relationship with the insect’s ability to fly and the concentration of lipase in its flight muscles. Good fliers are equipped with larger quantities of lipase than are poor fliers. It is suggested that, like birds and locusts, butterflies also utilize fat for energy during sustained flight.
The Composition of the Haemolymph of the Larva of Drosophila Melanogaster
Authors: Croghan P. C. , Lockwood A. P. M.
Published: April 2021

The osmotic pressure, sodium, potassium and chloride concentrations have been determined in the haemolymph of normal Drosophila melanogaster larvae and of larvae selected to survive on standard medium containing 7% NaCl (‘selected’ larvae). The haemolymph composition of normal larvae developing on standard medium shows features characteristic of pterygote insects. The haemolymph of ‘selected’ larvae developing on standard medium containing 7% NaCl is markedly hypotonic to the medium. There is only a small rise in NaCl concentration. Both normal larvae and ‘selected’ larvae can survive and develop on standard medium containing 7% KCl. The haemolymph of ‘selected’ larvae developing on standard medium containing 7% KCl is markedly hypotonic to the medium. There is a decreased Na:K ratio and a very markedly increased Cl:organic anion ratio. The nature of the mechanisms regulating the haemolymph composition is discussed.
An Experimental Analysis of the Function of the Pseudobranch in Teleosts
Authors: Parry Gwyneth , Holliday F. G. T.
Published: April 2021

The effects of removal of the pseudobranch have been studied in four species of marine fish and two species of fresh-water fish. No evidence was found for any direct effect upon osmoregulation or respiratory exchange. Removal of the pseudobranchs was followed by the darkening of the fish, due to chromatophore expansion, and after some weeks, by the degeneration of the choroid gland in the eye. It is suggested that the pseudobranch produces, or activates, a hormone affecting the chromatophores and that the entry of this hormone into the general circulation is controlled by the choroid gland.
The Co-ordination of Swimmeret Movements in the Crayfish, Procambarus Clarkii (Girard)
Authors: Hughes G. M. , Wiersma C. A. G.
Published: April 2021

Electrical activity recorded in the first roots of the abdominal nerve cord show bursts of activity which accompany rhythmic movements of the swimmerets. These bursts persist when a root is cut distal to the electrodes. Proprioceptive impulses have been recorded from the distal portion of these nerves during passive movements of the swimmerets. They have also been recorded in the connectives during both passive and active movements. Cutting all second and third roots of the abdominal ganglia does not interfere with the rhythmic swimmeret movements of the isolated abdomen. Rhythmic efferent bursts persist in first roots even when only a single first root remains intact in such a preparation. Intermittent bursts are also found in the first roots of a completely isolated cord but their pattern, frequency and phase relationships differ from those recorded in the same roots before isolation was completed. Such bursts are very rare in second and third roots. Stimulation of small bundles of fibres in the circumoesophageal commissure produces well-defined inhibitory and excitatory effects on the discharge of single units in the first roots. One specific bundle found in many preparations, when stimulated at 50/sec., caused a tonic retraction of all the swimmerets which then began to beat rhythmically and continued to do so when stimulation was discontinued. Intermittent bursts in the first roots took place with correct phasing during this stimulation even when the abdominal ganglia were isolated except for their connexion with the last thoracic ganglion. Again, such bursts were absent in the second and third roots. It is concluded that both the inflow from peripheral proprioceptors and intrinsic properties of the central ganglia play essential parts in the co-ordination of the metachronal movements of the swimmerets.
The Effects of Ions and Drugs on Neuromuscular Preparations of Sea Anemones
Authors: Ross D. M.
Published: April 2021

Isolated marginal sphincters of Calliactis and Metridium show little spontaneous activity, but over a limited frequency range give quick facilitated contractions to not less than two stimuli, and slow contractions having latencies of many seconds to multiple stimuli over a wider frequency range. Earlier observations on the effects of ions on whole animals are confirmed and extended. Excess K+ causes spontaneous quick contractions and responses to single stimuli ; excess Ca2+ has no direct excitatory effects, but causes an immense enhancement of the quick response without affecting the slow response to stimulation ; excess Mg2+ abolishes both quick and slow contractions. Most drugs, including acetylcholine and its associates, histamine, and 5-hydroxytryptamine, have no effects on either quick or slow contractions. Important effects occur only with tyramine, tryptamine and adrenaline at concentrations of 1 × 10−5 and 1 × 10−4. No inhibitory drug was discovered. Tyramine has no direct excitatory effects but it greatly enhances the quick facilitated responses without enhancing (and in some circumstances depressing) the slow responses to stimuli. It also causes small responses to single stimuli. Tryptamine causes direct quick contractions of the sphincter, gives quick responses to single stimuli and somewhat enhances both quick and slow responses to stimuli. Adrenaline has no effect on quick facilitated responses but causes direct slow responses and some enhancement of slow responses to stimuli. The effects of ions and drugs are obtained only when they are applied directly to the sphincter region. They do not occur when they are applied only to an attached strip of column. It is noted that the effects of excess K+ and tryptamine are identical, and that the effects of excess Ca2+ and tyramine are also identical; adrenaline stands alone as a ‘slow-excitor’. The physiological significance of the results is discussed in relation to different components of the responding system and to the mechanisms of quick and slow contraction in the sphincters.
Hearing and the Octopus Statocyst
Authors: Hubbard S. J.
Published: April 2021

A detailed study of the anatomy of the octopus statocyst by Young (1960) seemed to indicate that, although the maintenance of equilibrium was likely to be its most important function, the possibility of its participating in the function of hearing could not be ruled out. The work described here was an attempt to test this possibility.
Survival of Goldfish in Presence of Carbon Monoxide*
Authors: Anthony E. H.
Published: April 2021

The importance of Hb for certain aspects of goldfish respiration has been tested by converting it to COHb. Goldfish exposed to 80 % CO and 20 % O2 survived over 24 hr. at 30 ° C., and indefinitely longer at lower temperatures. Routine activity of goldfish over most, if not all, of their thermal range does not depend upon Hb. Removal of dissolved O2 from water under asphyxiai conditions does not depend upon Hb. While the physiological basis of CO2 tolerance curves remains unresolved, it can be said that they do not indicate an effect of CO2 upon Hb. Apparent changes in sensitivity to CO2 that have been ascribed to changes in thermal environment are probably artefacts arising from variation in the solubility of CO2.
Sodium Balance in Eriocheir Sinensis (M. Edw.). The Adaptation of the Crustacea to Fresh Water
Authors: Shaw J.
Published: April 2021

In Eriocheir sinensis active uptake of sodium plays a vital role in the maintenance of sodium balance. At external concentrations down to about 6 mM./l. the active uptake mechanism is fully saturated and the uptake rate just balances the rate of loss, which occurs primarily through the body surface. At lower external concentrations balance may be achieved, at least in part, by the activation of the uptake mechanism. A hypothesis is put forward to account for the mechanism of adaptation of the Crustacea to fresh water. Two main factors are involved: (a) a progressive reduction in the permeability of the body surface to salts and, (b) the acquisition of an active uptake mechanism with a high affinity for the ions which it transports. This hypothesis is discussed in relation to previous theories on the adaptation of the Crustacea to fresh water.
The Spectral Sensitivity of Calliphora Maggots
Authors: Strange Priscilla H.
Published: April 2021

If fly larvae are put on a table by a window they immediately begin to travel away from the light. Turn the table round, and the maggots change direction so as to move directly away from the light again. They travel by a ‘tacking’ process—the head end is extended to right and left alternately, and each time the rear end is drawn after it. The animal moves on a straight course if this process is symmetrical; should a movement of the head bring it into a region of higher illumination or other undesirable condition the head is withdrawn, and a second step made to the opposite side, turning the animal round.
The Influence of Sex and Size on the Osmotic Pressure, The Chloride and the Free Amino Acids of the Blood of the Freshwater Field Crab, Paratelphusa Sp. and the Freshwater Mussel, Lamellidens Marginalis
Authors: Padmanabhanaidu B. , Ramamurthy R.
Published: April 2021

The influence of sex and body size on the osmotic pressure, chloride and free amino acids in the blood of the freshwater field crab, Paratelphusa sp., and the freshwater mussel, Lamellidens marginalis, were investigated. In the crab the osmotic pressure increased in both the sexes to a maximum at about 40 g. in males and at 35 g. in females and then fell with further increase in weight. Throughout the whole size range the males tended to have a higher osmotic pressure. Blood chloride in the crab also increased with weight in both the sexes to a maximum at about 40 g. in males and 35 g. in females and then steadily decreased as the weight increased. In the positive slope of the regression line the females have a higher blood chloride, but in the negative slope of the curve the males have higher blood chloride. The free amino acid content of the blood reached a maximum at about 32 g. in males and 35 g. in females and then gradually decreased as the weight increased. Over the whole size range the males tended to have higher free amino acid content than the females. In the freshwater mussel both chloride and free amino acid content of the blood showed a small but steady increase with increasing weight. This is also reflected in a significant increase in the blood osmotic pressure with increase in body weight.
A New System for Continuous Respirometry of Small Air-Breathing Invertebrates Under Near-Natural Conditions
Authors: Macfadyen A.
Published: April 2021

A new system of respirometry for long-term experiments on small air-breathing invertebrates is described for use in work where changing temperature conditions are essential. There is no reason why the same system should not be used for larger animals. The respirometer is of the Barcroft, compensating type, isolated from the atmosphere, and has provision for temperature equilibration in the two vessels. Oxygen is automatically replenished by electrolysis of copper sulphate solution in the chamber as it is used by the animal and the rate of replenishment is recorded. The main features in design of such an apparatus, its limitations and accuracy are discussed. The accuracy is comparable with that of a Warburg respirometer and the sensitivity, at better than 0·1 mm.3 of oxygen/hour, is about ten times as great. A special control and recording system has been developed in order to reduce expense and simplify the interpretation of the data from six respirometers over long periods. It is shown that the errors arising from temperature changes can be reduced to acceptable levels for most purposes. The apparatus is therefore suitable for use in the study of acclimatization and of responses to rhythmical temperature changes. Examples of respiration records are given which illustrate the possibilities of being able to follow respiration rates through several diurnal cycles. Practical details of construction are given in the appendices.
The Physical Properties of the Swimbladders of Some South American Cypriniformes
Authors: Alexander R. McN.
Published: April 2021

The physical properties of the swimbladders of a variety of Characinoidei, Gymnotoidei and Siluroidei were investigated and found to be essentially similar to those previously reported for Cyprinidae. The Siluroidei, however, which were all Bagridae, had much lower excess internal pressures than the other Cyprinifonnes.
Effect of Dissolved Oxygen Concentrations On the Toxicity of Several Poisons to Rainbow Trout (Salmo Gairdnerii Richardson)
Authors: Lloyd R.
Published: April 2021

A given reduction in the dissolved oxygen concentration of the water from the air-saturation value to a lower level increases the toxicity to rainbow trout of zinc, lead and copper salts, and of a mixture of monohydric phenols, to about the same extent. The effect of a reduced oxygen concentration on the toxicity of ammonia solutions is greater than that found for the other four poisons ; the extra increase can be accounted for by a theoretical calculation of the difference between the pH value of the bulk of the solution and that at the gill surface. An hypothesis is presented to account for the effect of low oxygen concentrations on the toxicity of poisons to fish. It assumes that a given toxic effect is produced by a specified concentration of poison at the gill surface, and suggests that this concentration is governed not only by the concentration of poison in the bulk of the solution but also by the velocity of respiratory flow.
Studies On Salt and Water Balance in Caddis Larvae (Trichoptera)
Authors: Sutcliffe D. W.
Published: April 2021

Limnephilus affinis larvae tolerate external salt concentrations up to at least 410 mM./l. NaCl (about 75 % sea water) and survive for short periods in 470 mM./l. NaCl (about 85 % sea water). The body wall is highly permeable to water, but relatively impermeable to sodium and chloride. Most of the sodium and chloride uptake from salt water occurs via the mouth. The sodium and chloride levels in the haemolymph are powerfully regulated. Both are maintained strongly hypotonic against large external concentration gradients. The Malpighian tubule-rectal system is very sensitive to changes in the haemo-lymph chloride level. The chloride concentration in the rectal fluid can be at least three times greater than the concentration in the haemolymph, and slightly greater than the concentration in the external medium. The rectal fluid is hyper-osmotic to the haemolymph and to the medium at high external salt concentrations. At external concentrations greater than about 200 mM./l. NaCl, water balance is maintained by regulating the haemolymph roughly iso-osmotic with the medium. This is partly achieved by increasing the non-electrolyte fraction in the haemolymph. A small quantity of osmotically free water is available to replace any osmotic loss. This can be obtained by drinking salt water and producing a concentrated solution of salts in the rectum.
Colonial Responses of Hydroid Polyps
Authors: Josephson Robert K.
Published: April 2021

Conduction of excitation in response to local mechanical or electrical stimulation has been studied in various hydroid species. There are systems in the coenosarc of the stems and stolons of all species which conduct excitation at rates of from 1 to 3·5 cm./sec. Two physiological types of conducting systems have been found. Through-conducting systems, showing: all-or-none response, sharp threshold, reproducibility. Local systems, showing : spread of response dependent upon stimulus strength, no sharp threshold, responses which decline with increasing distance from the stimulated point, variability. Colonial co-ordination is better developed in those species whose colonies are structurally better developed. It is effected in most species by either (a) or (b). Both types are present together in Hydractinia echinata.
Two Phases of Ageing in Drosophila Subobscura
Authors: Clarke Jean M. , Smith J. Maynard
Published: April 2021

Male and female D. subobscura were kept for varying periods at low temperatures (3−20°C.) and then transferred to a higher temperature (26−30°C.) and kept there until they died. It was found that during the early part of the life span, over the range 15·30°C., every day spent at a low temperature reduced the expectation of life at a higher temperature by approximately i day. Later, when the expectation of life at the higher temperature had fallen to about half its initial value, little further change in this expectation occurred with increasing age at a lower temperature. It is concluded that the life span can be divided into two phases, (i) an irreversible ‘ageing’ process whose rate is approximately independent of temperature from 15 to 30°C., but which is slower at 3°C., and (ii) a ‘dying’ process which is initiated when ageing has proceeded to a stage at which the individual is no longer capable of maintaining a steady state at the temperature at which it is living, although the same individual would be capable of maintaining a steady state at some lower temperature. The rate of the dying process is highly dependent on temperature, and it can be reversed in flies transferred to lower temperatures.
Receptor Potentials Recorded from Sensilla Basiconica on the Antenna of the Silkworm Larvae, Bombyx Mori
Authors: Morita H. , Yamashita S.
Published: April 2021

Several authors have reported on electrical activities of antennae of insects in response to various olfactory stimuli (Boistel, 1953; Roys, 1954; Boistel, Lecomte & Corabœuf, 1956; Schneider & Hecker, 1956; Schneider, 1957). Dethier (1941) studied the sensilla of the antenna of lepidoptera larvae, and assumed that the ‘large’ sensilla basiconica were olfactory organs.

One of the authors (Morita, 1959) recorded slow potentials directly related to occurrence of impulses (i.e. receptor potentials) from the side wall of the contact chemosensory hair on the labellum of the blow-fly, Calliphora vomitoria. The ‘large’ sensilla basiconica on the antennae of lepidoptera larvae are far smaller than the labellar chemosensory hair, but not so small as to prevent application of the method available for the labellar hair. In the present study, using this method, electrical activities of the sensillum basiconicum of the silkworm larva were qualitatively analysed.
Aspects of the Organization of Central Nervous Pathways in Aplysia Depilans
Authors: Hughes G. M. , Tauc L.
Published: April 2021

There has been little recent work on the relationship between the behaviour of gastropod molluscs and the activity of their nervous systems. Older workers (e.g. ten Cate, 1928), studied the effects of electrical stimulation of different nerves on the movements of parts of the animal. More recently observations on the spontaneous activity and electrical properties of individual cells in isolated ganglion preparations have been extensively carried out (Arvanitaki, 1942; Tauc, 1955, 1957a, b, 1958, 1960a; Hagiwara & Saito, 1959), but little attention has been paid to the importance of these phenomena in the life of the animal. Furthermore, deductions concerning the behaviour of gastropods based on observations of the activity in isolated ganglia are necessarily tentative (Hughes & Kerkut, 1956). The most recent study of neuronal pathways is that of Turner & Nevius (1951) on Ariolimax columbianus. They used external electrodes in stimulation and recording experiments and made tentative proposals concerning the layout of some of the typical neuronal connexions. As they point out, little is known of the connexions between neurones, and anatomical methods are unable to provide sufficient information about the nature of neuronal connexions over long distances. Nisbet (1961) has recently recorded impulses in the pallial nerves of Archachatina in response to tactile stimulation and has studied conduction in the nerves and across ganglia. Techniques similar to those of Turner & Nevius have been used in the present work but in addition intracellular micro-electrodes have been employed for recording the activity of individual cells in whole animal preparations. This technique is extremely valuable as the pattern of activity of single units, now well known from such cells in isolated preparations (Tauc, 1960a), gives additional information about the paths of single neurones over quite large distances.
The Imaginal Ecdysis of Blowflies. The Control of Cuticuar Hardening and Darkening
Authors: Cottrell C. B.
Published: April 2021

Blood transfusion experiments show that normal hardening and darkening at the imaginal ecdysis of Calliphora eryihrocephala(Meigen) is brought about by the release into the blood of an active factor. Introduction of this factor into a newly emerged fly some 35 min. prior to the time at which it would normally be released is sufficient to prlivent expansion. The factor is normally released some 45 min. before the appearance of the first signs of darkening and between 3 and 15 min. after the fly has reached conditions suitable for expansion, that is at about the time of initiation of air-pumping. Decapitation at emergence will prlivent the initiation of normal hardening and darkening but not of secondary darkening. Evidently the head is concerned in the release or the control of the release of the blood-borne darkening factor. The critical period for the prlivention of normal hardening and darkening by decapitation lies between 3 and 15 min. after the fly has reached conditions suitable for expansion. Isolated abdomina behave in a manner similar to decapitated flies but their reactions are complicated by secondary darkening associated with damage. Flies deprived of their abdomina will expand at least partially but the rate of their hardening and darkening is reduced. Damage reactions resembling secondary darkening in digging flies are more extensive after damage to internal organs such as the gut than to superficial organs such as the body wall. Allowing for the effects of secondary darkening it is possible to demonstrate the occurrence of the blood-borne darkening factor by means of ligatures placed at emergence between the thorax and the abdomen. Under these conditions only the head and thorax exhibit normal darkening.
Experiments On Choice of Substrata by Spirorbis Larvae (Serpulidae)
Authors: De Silva P. H. D. H.
Published: April 2021

Spirorbis borealis occurs typically on Fucus serratus, S. corallinae on Corallina officinalis and S. tridentatus on rocks and stones. Laboratory experiments showed that the larvae of each species select the substratum on which the species typically occurs, the substrata of the other two species and a variety of other substrata being either less favourable or very unfavourable. Larvae of S. borealis tend to be geopositive and photopositive when settling. Those of S. tridentatus are geopositive but overridingly photonegative, which explains the natural occurrence of this species in dimly lit places.
The Reaction of Blinded Goldfish to Rotation in A Centrifuge*
Authors: Howland H. C. , Howland B.
Published: April 2021

Blinded goldfish behave in a centrifuge as if they were orienting to absolute rotation by means of a Foucault pendulum. That is, they swim so as to compensate the rate of imposed rotation about the apparent vertical. Blinded goldfish swim in the centrifuge in a plane essentially orthogonal to the apparent vertical at low accelerations and low rates of rotation. With higher rates of rotation the axis about which the fish swims leans away from the apparent vertical and towards the axis of rotation of the centrifuge. Analysis of the physics of the centrifuge shows that if the fish rotates about any axis relative to the cab of the moving centrifuge with a rate of rotation within the physiological range of its semicircular canals it will receive signals from its otocysts and its semicircular canals which would reflect contradictory information in a nonrotating environment. This fact, together with the fish’s response to absolute rotation, affords a method for quantitatively assessing the relative roles of the otocysts and the semicircular canals in orienting the free-swimming fish.
Patterned Activity of Co-Ordinated Motor Units, Studied in Flying Locusts
Authors: Wilson Donald M. , Weis-Fogh Torkel
Published: April 2021

A brief survey of the locust flight system is presented as background for this and future studies. Included are descriptions of the wing movements, the aerodynamic parameters and the pertinent muscle anatomy and physiology. A procedure has been designed which makes it possible to study a complex locomotory pattern in terms of the activities of single nervous and muscular units, in this case during normal flight of locusts. We have found a detailed repetitive pattern which is precisely correlated with the wing movements. Fig. 24 shows the pattern during normal flight. Variations in the details of the pattern are also correlated with significant variation in the movements. During average flight most of the flight motor units fire a single time per wing stroke. In low-powered flight numerous units are inactive. With increase in power additional units are recruited and active ones may fire twice or more during a specific phase of a single wingstroke. Increase in wingstroke frequency is correlated with increase in number of active units and with earlier onset of activity so that the wing movements are braked at top and bottom by muscular activity as well as by other restoring forces. Lift is controlled by changes in wing twisting which are mainly due to changes in activity of a single two-unit muscle for each wing, the subalar muscle.
An Experimental Study of the Cells of the Hepato-Pancreas of Ligia
Authors: Patrick Dorothy M.
Published: April 2021

In order to study the cells of the hepato-pancreas, a number of Ligia oceanica were procured from the Marine Laboratory at Plymouth. They were kept alive by feeding on decaying animal and vegetable matter moistened with sea-water.
The Mechanism of Cell-Division
Authors: Gray J.
Published: April 2021

The fact that dividing cells are usually only found in actively growing tissues does not necessarily prove that growth and cell-division are two closely correlated phenomena. Growth may be defined as an increase in the amount of organised material which is present in the cell and which is essentially part of the living machine. Cell-division, on the other hand, only implies the cleavage of the cell into two or more parts. The purpose of this work is to enquire into the relationship between the two phenomena when they are taking place together. The material used was the segmenting eggs of Echinus miliaris.
Some Effects Produced By the Hooding of Birds
Authors: Patrick Dorothy M.
Published: April 2021

A Black velvet hood was placed over the head of a pigeon and tied round the neck with a piece of cotton, sufficiently tight to prevent the bird removing it with its claws, which it at once attempted to do. Presently some movements of progression were made along the floor, which seemed to suggest that disturbances of equilibration had supervened ; then the bird rapidly became quiescent and assumed a peculiar and unusual position, in which the head was bent over until the crown rested upon its back, with the tip of the beak pointing towards the tail.
The Relationship of the Cortex Supra-Renalis and Testes Throughout Life in the Rat
Authors: Watson Alexander
Published: April 2021

The object of this investigation is to throw further light upon the relationship of the cortex suprarenalis or inter-renal tissue with the interstitial cells of the testes.
Taste By Touch: Some Experiments With Octopus
Authors: Wells M. J.
Published: April 2021

A method of teaching Octopus chemotactile discriminations is described. The animals can be shown to be capable of distinguishing by touch between porous objects soaked in plain sea water and sea water with hydrochloric acid, sucrose or quinine sulphate added. They can detect these substances in concentrations at least 100 times as dilute as the human tongue is capable of detecting them in distilled water. They can be trained to distinguish between equimolar (0·2 mm) solutions of hydrochloric acid, sucrose and quinine. They can also be trained to distinguish between sea water and fresh water or half-strength sea water or sea water with twice the usual quantity of salt. The function of the ‘olfactory organ’ is discussed. Chemotactile learning is discussed in relation to the means by which Octopus finds its way about the territory around its ‘home’.
The Filter-Feeding of Artemia
Authors: Reeve M. R.
Published: April 2021

The ability of filter feeders to discriminate between particles of different kinds was given an experimental basis in the work of Harvey (1937), who found that Calanus feeding in a mixed suspension of Lauderia and Chaetocerus would take little of the latter. Marshall & Orr (1955) could not confirm these observations and in experiments with mixed suspensions of various plant cells found no clear evidence of any selection mechanism, as also did Ryther (1954) using Daphnia.
The Change of Discharge Frequency by A.C. Stimulus in A Weak Electric Fish
Authors: Watanabe Akira , Takeda Kimihisa
Published: April 2021

A South American gymnotid Eigenmannia, changes the discharge frequency of its electric organ when a weak electric signal is applied to it with a frequency very close to that of its own discharge. Otherwise, the discharge frequency is extremely constant at a fixed temperature. When the frequency of the applied signal is higher or lower than that of the fish discharge, the response is a decrease or increase of the discharge frequency, respectively. When the two frequencies are exactly the same, the response fails to occur. The threshold of this response is very low. In one fish it was about 3 μV./cm.
A Study on the Mechanism of Cleavage in the Amphibian Egg*
Authors: Dan K. , Kojima M. Kuno
Published: April 2021

In comparison with the large number of investigations performed on the cleavage of sea-urchin eggs, those on the cleavage of amphibian eggs are surprisingly scanty. Recent works are almost limited to two papers from Edinburgh by Waddington (1952) and by Selman & Waddington (1955). The present report is an amplification of the works of the British investigators.
Phasic Stimulation of A Thoracic Stretch Receptor in Locusts
Authors: Gettrup Erik
Published: April 2021

Phasic sinusoidal and constant-velocity deformation was applied to a stretch receptor from the thorax of the desert locust, Schistocerca gregaria Forskil. The response was analysed with respect to the main parameters of the stimulus. The stretch receptors respond to the flight movements with 1 – 3 potentials per wing-stroke cycle. Special interest was therefore given to the first potentials of the response. At constant frequency of stimulation the phase angle of the first potential of the response was found to be independent of changes in length and length-time parameters. The period between the two first potentials was found to be related to velocity in a rather complex way. At constant frequency, the number of impulses is a linear function of maximum displacement and/or velocity. The functional significance of the relations is discussed in relation to coordination of flight and a hypothesis is proposed which explains the constancy of the wing-stroke period as the result of a stabilizing influence of the first potential of the response.
Micropuncture Studies of Chloride Concentration and Osmotic Pressure in the Crayfish Antennal Gland*
Authors: Riegel J. A.
Published: April 2021

Chloride concentration and freezing-point depression (=osmotic pressure) have been measured on samples of urine obtained from various parts of the crayfish antennal gland by micropuncture. The chloride concentration of the urine is significantly below that of the blood in all parts of the antennal gland, but a marked drop is not seen until the distal tubule is reached. The urine becomes progressively hypo-osmotic to the blood in the labyrinth, distal tubule and bladder. In the coelomosac, it is iso-osmotic; possible reasons for this are discussed. Chloride concentration and osmotic pressure are lower in urine taken from the nephropore than in urine taken from the distal tubule near the place where it joins the bladder. This suggests that the bladder is in part responsible for the production of hypotonic urine. The results of the present study are discussed in relation to the theory that filtration (in the limited sense discussed by Riegel & Kirschner, 1960) is the mechanism by which primary urine is formed in the crayfish antennal gland.
Some Observations On the Actions of Steroids On the Metaplasia of the Amoeba, Naegleria Gruberi
Authors: Pearson Janet L. , Willmer E. N.
Published: April 2021

The age of the culture of Naegleria gruberi, i.e. the time since the last subculture, is of little importance in determining the numbers of cells which turn flagellate when placed in the extremely dilute buffer solutions used. Between 17° and 21°C. there is a very great decrease in the time which the amoebae require in order to become flagellate when placed in buffer solution. There is no evidence that the amoeba, as such, differentiates between solutions of KCl or NaCl. On the other hand, the flagellate form is somewhat more reactive to KCl than to NaCl, and fewer flagellates are found in KCl solutions. The metaplasia is affected by the presence of steroids in the medium. The more interesting actions of the steroids tested may be summarized as follows. At high concentrations, progesterone and deoxycorticosterone, when applied to the amoeba, prevent the change to the flagellate form. When applied to the flagellate, progesterone has little action, but deoxycorticosterone encourages the return to the amoeboid form, especially in the presence of K+. In lower concentrations both steroids favour the change from amoeba to flagellate and also from flagellate to amoeba. Other steroids have characteristic effects. While the dose/response curves indicate qualitatively different effects of concentration of progesterone and deoxycorticosterone they only show quantitatively different effects with oestradiol and androsterone. Progesterone acts on amoebae at concentrations which are comparable with those at which it acts in the human body. When both progesterone and oestradiol are applied together at concentrations which suppress the flagellate form the effects are additive. The same applies to mixtures of testosterone and oestradiol. An activating concentration of progesterone has not yet been tested in combination with an inhibiting dose of oestradiol.
The Effect of the Web On Vibration Sensitivity in the Spider, Achaearanea Tepidariorum (Koch)*
Authors: Walcott Charles
Published: April 2021

The common house spider, Achaearanea tepidariorum, has a sensitive vibration receptor in each of its eight legs. The receptor has been shown to respond to air-borne sound as well as to direct vibration (Walcott & Van der Kloot, 1959). But for a spider on its web a more usual source of information about the outside world comes from vibrations of the web strands themselves. What is the response of the receptor to the vibrations of the web? Liesenfeld (1956, 1961) has described some of the properties of spider webs and recorded the electrical response of the vibration receptors of a variety of species of spiders to vibrations of the substrate. Nowhere, however, can one find information on how vibrations of the web are translated by the spider’s vibration receptor into electrical impulses in the sensory nerve.
Contact Chemoreception, Mating Behaviour, and Sexual Isolation in the Rotifer GenusBrachionus
Authors: Gilbert John J.
Published: April 2021

Matings in two commonly co-occurring, limnetic species of the genus Brachionus, B. calyciflorus and B. angularis, are completely species-specific. Males initiate mating reactions only when they happen to swim head-on into females of their own species. In these reactions the male maintains contact with the female and simultaneously moves round and round her body until either he loses contact and swims away or he copulates. Females play an entirely passive role throughout the mating process. The male mating reaction is the manifestation of an innate reflex response which is triggered when certain coronal chemoreceptors make contact with, or are exposed to, a sudden, marked increase in concentration of a species-specific chemical substance located only in the females of the species. This substance, which is continually released into the environment by growing females and is extractable from crushed females with water, is: dialysable, ether-insoluble, heat-stable, acid-stable, base-labile, resistant to periodate oxidation, adsorbed on charcoal, amphoteric, and unaffected by trypsin, pepsin, and carboxypeptidase.
Frog Fast Muscle
Authors: Pennycuick C. J.
Published: April 2021

A method is described for producing a family of curves of mechanical power output against tension, with time as parameter, in an isometric twitch. It is found that these differ from corresponding curves produced from the same muscle under isotonic conditions. A method is described of simulating a variable mass against which the muscle can contract. The time course during a twitch of the power expended in moving this mass, and of that expended in stretching the series compliance, is determined. In the early (‘active’) part of the twitch the total power agrees well with that predicted from isotonic measurements, but in the latter part (‘tail’) the muscle’s behaviour abruptly changes : it then resembles, with some differences, a large viscous resistance, in a manner which is compatible with the form of isometric twitches, but has no parallel under isotonic conditions. The power developed in certain phases of the isometric twitch falls short of that predicted from isotonic measurements. It is shown that this can be explained by postulating an upper limit to the rate at which the contractile component can develop tension, and supposing that this limit declines as the twitch proceeds.
The Landing Responses of Insects
Authors: Goodman Lesley J.
Published: April 2021

The electroretinogram of Lucilia sericata has been recorded whilst the fly was stimulated by an approaching object and by a slow change of light intensity. The approach of a dark object against a light background was accompanied by the gradual development of a negative potential which decayed rapidly when movement ceased. The size of the potential change was found to be directly proportional to (a) the number of ommatidia stimulated by the approaching object, (b) the rate of the decrease and (c) the amount of the decrease of intensity which it produced. A similar response could be produced by stimulating the fly with a decrease of intensity, the negative potential developed being directly proportional to the number of ommatidia stimulated, to the rate and to the amount of the decrease.
Tactile Discrimination of Surface Curvature and Shape by the Octopus
Authors: Wells M. J.
Published: April 2021

Experiments are described in which octopuses were trained to discriminate by touch between pairs of Perspex cylinders of different diameter. The proportion of errors made in experiments with thirteen different pairs of cylinders shows that octopuses distinguish cylinders on a basis of the difference in their surface curvature. Curvature is detected from the degree of distortion of individual suckers. The bend of the arm or arms grasping an object can be shown to be irrelevant by using composite cylinders built up from narrower rods. These are treated as being of the diameter of their components. Having been trained to take the larger and reject the smaller of two cylinders, octopuses tested with rough and smooth objects of the same size reject the rough and accept the smooth. Apparently the sensory input produced by contact with an object having a rough surface is similar to that produced by bending the suckers round a smooth curve of narrow radius. The discrimination of cubes and spheres, which appears to be based on sucker distortion at the corners of the cube, is upset by cutting grooves into the surfaces of the two objects. These findings are discussed in relation to the anatomy of the sense organs in the suckers. The development of two parallel mechanosensory systems, one related exclusively to the local adjustment of muscle tension, the other more concerned with the animal’s relations to its external environment and hence involved in learned responses, is common to the organization of cephalopods and vertebrates.
Osmotic Balance in Hydrobia Ulvae and Potamopyrgus Jenkinsi (Gastropoda: Hydrobiidae)
Authors: Todd Mary E.
Published: April 2021

Osmotic balance was studied in Hydrobia ulvae and Potamopyrgus jenkinsi over the range 100% sea water to fresh water, by determining the freezing-point depression of the urine in the different solutions. Hydrobia ulvae was slightly hyperosmotic from 100 to 50 % sea water, and sometimes initially markedly hyperosmotic in 25 % sea water at 5° C. The urine was always markedly hyperosmotic relative to fresh water, and the animals were withdrawn. Experiments with phenol red indicated that the tissues were not shut off from the medium. Potamopyrgus jenkinsi was hyperosmotic from fresh water to 100% sea water. Osmotic balance in fresh water is maintained in part by the excretion of a urine hypo-osmotic relative to the blood. There was some variation in the reaction of different ecological groups of Hydro-bia ulvae and Potamopyrgus jenkinsi to the experimental conditions. In the Hydrobiidae, whether transformed from a lower to a higher salinity or vice versa, survival outside the viable range was longer at 5° C. than at 15° C., although, within the range, activity occurred more rapidly at 15° C. In fresh water, winter animals of both species had a higher osmotic concentration of the urine than summer animals, but no differences in osmotic concentration correlated with temperature were demonstrated.
The Evaporation of Water From Helix Aspersa
Authors: Machin John
Published: April 2021

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

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

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

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).