bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Excretion of Magnesium by Carcinus Maenas
Authors: Lockwood A. P. M. , Riegel J. A. 
Published: April 2021

ABSTRACT
Measurements have been made of the concentrations of sodium, calcium and magnesium in the blood and urine of Carcinus maenas after transfer to 50 or 150% sea water. Inulin clearance studies were also made. Magnesium is concentrated in the urine by a secretory process when the crabs are in 100% sea water or 150% sea water. There is evidence that the rate of secretion declines when the crabs are in 50% sea water or in 100% magnesium-free sea water. There is no evidence for active withdrawal of magnesium from the urine. When the blood is depleted of this ion the U/B for magnesium drops to a value similar to the U/B for inulin. The clearance of inulin is faster when Carcinus is in 150% sea water than when it is in 100% sea water, and it is calculated that the animal excretes magnesium at a faster rate than it does in 50% sea water. The excretion of magnesium by Carcinus and Pachygrapsus is compared, and it is shown that magnesium is conserved more effectively in dilute media by Carcinus than by Pachygrapsus. This probably reflects differences in the ecology of the two species.
The Visual Mechanisms of Tenebrio Molitor: Variations Taking Place in the Erg of Pupa and Adult During Development
Authors: Yinon Uri , Auerbach Edgar 
Published: April 2021

ABSTRACT
The changes in the ERG of the compound eye of Tenebrio molitor were measured and followed in both the pupal and the adult stages. In the pupal stage the generally monophasic ERG was found to appear on the second day, and within 7 days reached an amplitude of 0·35 mV. The more complex ERG of the adult beetle increased in amplitude to more than 5 mV. during the following 14 days. The latent periods and peak latencies of the pupal and adult ERGs differed only slightly and did not display any consistent changes with age. 4 The morphological development of the eye was compared with the changes in the ERG.
Water Balance in Ilyocoris Cimicoides (L.) (Heteroptera; Naucoridae): The Rate of Net Water Uptake Through the Cuticle
Authors: Staddon B. W. 
Published: April 2021

ABSTRACT
Measurements have been made of the rate of net water uptake through the cuticle of adult females of Ilyocoris cimicoides(L). With a method that consisted in recording the increase in weight after sealing the external openings of the gut a value of about 10 % of the body weight per day was obtained for the rate of net water uptake through the cuticle at a temperature of 18° C. The Arrhenius equation appeared to hold over the temperature range 4− 26° C. and an approximate value of 10, 530 cals was obtained for the temperature characteristic, μ, of the rate of net water uptake over this range of temperatures. However, the values obtained for the rate of net water uptake at 1°C. (1·8% of the body weight per day) were less than straightline expectation between log. uptake and 1/T over the temperature interval 1− 26°C. would indicate. The results obtained by recording the increase in weight after sealing the external openings of the gut agreed well with those obtained by determining the difference between the intake of drinking water and output of rectal fluid, were somewhat less than the values obtained with a method that consisted in recording the increase in weight after death by ammonia poisoning, and were some four to live times greater than the theoretical values derived on a diffusional basis from the rate of entry of D2O. The results confirm previous evidence that adult waterbugs are typical freshwater animals in the sense that the excretory system must work continuously to eliminate water gained unavoidably and in appreciable amount by osmotic uptake through the cuticle.
The Ionic Relations of Artemia Salina (L.)
Authors: Smith P. G. 
Published: April 2021

ABSTRACT
Measurements of ion concentrations and of electrical potential difference and resistance have been made in Artemia salina, the brine shrimp, using animals acclimatized to sea water. It is believed that the results of the electrical measurements are largely determined by the characteristics of the gill epithelium. The potential difference between the blood and external medium in sea water is + 23 mV. (blood positive). Considered in relation to the ionic concentrations, this indicates that chloride is subject to active transport out of the animal, potassium is pumped in, and sodium is approximately in equilibrium. Measurements of potential difference in other solutions give the permeability ratios Na:K:Li:Cl as 1·00:0·6: 1·0:0·11. The resistance of the gill epithelium in sea water is 40 Ωcm.2. Measurements of resistance in other solutions suggest that lithium ions induce a decrease in cation permeability.
A Re-Examination of the Excretion of Nitrogen by Terrestrial Isopods
Authors: Wieser Wolfgang , Schweizer Gerhild 
Published: April 2021

ABSTRACT
In spring and summer specimens of Porcellio scaber feeding on old poplar leaves excrete from 0·46 to 1·12 ng. dissolved ammonia/mg. body weight × hr. via the faeces, and from 2·3 to 3·25 ng. in gaseous form via the body wall. Non-feeding specimens excrete an average of 11 ng. ammonia/mg. × hr. in gaseous form. In the course of a normal cycle in which periods of feeding activity alternate with periods of inactivity (temporary starvation), faecal ammonia thus constitutes only 10% of the total ammonia released by the animals. If the gaseous component is taken into account, the rate of nitrogen excretion in terrestrial isopods is comparable with that of fresh water and marine species. Oniscus asellus and P. scaber excrete approximately five times more ammonia in spring and summer than in autumn and winter. The faeces produced by P. scaber contain an average of 220 μg. total nitrogen/ 10 mg. of dry faeces of which 2−4% consist of ammonia. Following abrupt changes of temperature, from 5 to 20°C. and from 20 to 5°C. the rates of the release of ammonia and of the production of faeces follow similar time courses, increasing with an initial Q10 of 3·7 if the change is from the low to the high temperature, decreasing with an initial Q10 of 4·6 if the change is in the opposite direction. It is suggested that in terrestrial isopods nitrogen output in the form of gaseous ammonia more or less balances nitrogen input from leaf litter (the animals’ main source of food) and that no reduction of protein metabolism takes place in terrestrial species of isopods as compared with aquatic species.
Studies on Fresh-Water Osmoregulation in the Ammocoete Larva of Lampetra Planeri (Bloch)
Authors: Morris R. , Bull J. M. 
Published: April 2021

ABSTRACT
Sodium influx in ammocoete larvae increases exponentially with external sodium concentration (0-1.0 mm/l.) and sodium-depleted animals show a 20% increase compared with normal animals. Sodium loss decreases as the environmental concentration decreases, although the reverse situation is expected from considering diffusion outflux alone. It is argued that part of the sodium loss is back-transported by the transport mechanism and this accounts for the reduced sodium loss from sodium-depleted animals whose sodium carrier activity is increased. The curves relating back-transport to environmental sodium differ from those derived by Kirschner for isolated frog skin. Sodium influx increases as sodium loss increases, indicating a self mechanism whose features are discussed. In the ammocoete, the sodium carrier mechanism appears to change in affinity for sodium (short-term response) and can also change in concentration (long-term response), and it is suggested that these features, together with permeability changes, may form the basis of the controlling mechanism for sodium balance.
Giant Fibre and Small Fibre Pathways Involved in the Evasive Response of the Cockroach, Periplaneta Americana
Authors: Dagan D. , Parnas I. 
Published: April 2021

ABSTRACT
Giant fibres were found not to activate leg motoneurones during evasion. A pathway of small axons having a conduction velocity of 1 ·5 −3 ·5 m./sec. was found to govern leg activation during escape. This pathway remains functional after giant-fibre degeneration after the giant axons have been severed from their somata. Movements of the antennae were found to be activated by the giant fibres simultaneously or slightly earlier than movements of the legs. It is suggested that a general alarm system is activated by the giant fibres concomitantly with activation of the leg motoneurones by a slower conducting pathway.
Neuromuscular Physiology of the Closer Muscles in the Pedipalp of the Scorpion Leiurus Quinquestriatus
Authors: Gilai Arieh , Parnas I. 
Published: April 2021

ABSTRACT
The closing system of the pedipalp claw in the scorpion is composed of two agonistic muscles situated in both the patella (the longer closer muscle) and tibia (the short closer muscle). Membrane electrical constants of the muscle fibres were found to be : λ = 0·6 mm.; ri = 1 × 106 Ωmm.−1; Ri = 280 Ωcm. ; rm= 4·4 × 105 Ωmm. ; Rm = 830 Ωcm.2; Cm. = 3·6 μF. cm.−2; τ = 3·0 msec.; input resistance = 3·3 × 105 Ω. Each muscle fibre is multiterminally innervated by two motor axons, one initiating a junction potential and the second inducing a post-synaptic spike-like response. The long closer muscle is composed of two anatomically distinct motor units, the short closer muscle of three motor units. Each unit is innervated by its own pair of specific motor axons. No distinction between ‘slow’ and ‘fast’ axons or muscle fibres could be observed. Both muscles responded with a twitch to a single stimulus applied to the nerve. No peripheral inhibition was observed.
Short and Long Memories in Octopus and the Influence of the Vertical Lobe System
Authors: Young J. Z. 
Published: April 2021

ABSTRACT
Octopuses from which either the median superior frontal or the vertical lobes have been removed show reduced capacity to learn to attack an unfamiliar figure. The duration of the increased tendency to attack after feeding is reduced by both operations. This suggests that the failure to learn is due to interruption of a self-re-exciting circuit. Although these operated animals would not attack rectangles they continued to attack crabs for much longer than controls, in spite of shocks. They also retained signs of this inhibition less well. When the median superior frontal lobe alone had been removed the remaining vertical lobe was able to exercise considerable restraint by virtue of its input from below. This shows that the effect of this lobe in preventing attack at a particular figure cannot be wholly due to pre-synaptic inhibition, since the effect can appear when the relevant pre-synaptic fibres are absent. The ‘pain’ fibres are therefore able to activate the vertical lobe to produce inhibition of the system that produces attack at a particular shape.
Lipid, Bile Acid, Water and Dry Matter Content of the Intestinal Tract of Domestic Ducks with Reference to the Habitat of Polymorphus Minutus (Acanthocephala)
Authors: Crompton D. W. T. , Nesheim M. C. 
Published: April 2021

ABSTRACT
The distributions of total material, water, lipid and bile salts in the intestine of domestic ducks feeding ad libitum have been determined. Most material accumulates in the posterior part of the intestine and the duodenal region appears to be wetter than the rest of the intestine. When ducks feed on a diet with a lipid content of 4% of the dry weight, the highest concentration of lipid detected in the intestine was 5 % of the dry weight of the ntestinal material. Lipid appears to be absorbed in the anterior half of the intestine. Bile acids accumulate in the posterior part of the intestine where concentrations as high as 5·18 mg./g. of intestinal contents were detected. The evidence indicates that bile acids are absorbed in the posterior part of the intestine. The bile acids of bile from the gallbladders of ducks have been identified by means of gas-liquid chromatography. Cholic acid, chenodeoxycholic acid, lithocholic acid and some unidentified substances were found to form 16, 59, 17 and 8%, respectively, of the bile acids. The results are discussed with reference to Polymorphus minutus, an acanthocephalan parasite of ducks.
The Orientation of Locusts to A Lamp After Unilateral Injury
Authors: Makings P. , Hussain C. A. 
Published: April 2021

ABSTRACT
Injury to one side of the face, whether on the frons or an antennal patch, affects the orientation of adult locusts to a lamp. For the first 5 days after injury most of them turn the injured side towards the lamp. This tendency is lost or reversed after the fifth day. The change is most evident with a lamp of relatively high power (100 W.); with weaker lamps (60 or 40 W.) the differences are not statistically significant after five days. This phenomenon explains the finding of previous authors that the injured side is usually turned away from a lamp. When the results of numerous tests are added together, those obtained more than 5 days after injury can swamp the earlier ones. Suggested interpretations include the possibility that injury makes the damaged part ‘numb’ until type II neurones are formed in the healed area.
The Mechanics of Stridulation in Bush Crickets (Tettiginioidea, Orthoptera)
Authors: Bailey W. J. , Broughton W. B. 
Published: April 2021

ABSTRACT
Using isolated tegmina of the bush cricket Homorocoryphus nitidulus vicinus (Walker) mounted on the actuator described in a previous paper the parameters controlling tooth-impact rate have been varied. Results have shown that the mirror frame can be thrown into resonant vibration at between 12 and 15 kHz. when the tooth-impact rate approaches these values. The situation in the Homorocoryphus type of stridulation is compared with that of the Conocephalus type where resonance does not occur. The tooth-impact rate in H. n. vicinus is coupled with the frequency of natural vibration of the mirror frame via a plectrum-pivot-frame system which is made to act as a cantilever with the pivot at the mesial end of the vestigial file and the plectrum as the point of excitation. The problem of acoustic coupling involving mechanical and air-column systems is discussed.
Yaw-Correcting Postural Changes in Locusts*
Authors: Camhi Jeffrey M. 
Published: April 2021

ABSTRACT
Changes in the angle of the relative wind sensed by the facial wind receptors of a locust evoke fast rudder-like movements of the abdomen and legs whose magnitudes are proportional to the change of wind angle. This system is sensitive to the angular velocity of the wind change. Such wind changes also evoke rotations of the head about the long axis of the body. The head rotation induces, through proprioception by the cervical hair receptors, slow, redundant rudder-like movements of abdomen and legs. Control elements for the fast movements of abdomen and legs and for the head rotation appear not to be precisely co-ordinated and seem to include no proprioceptive ‘crosstalk’. All these responses are evoked by wind-angle changes only if the insect is flying at the moment, suggesting that flight closes a neuronal switch. Separate motor pathways seem to be employed for the abdomen’s rudder-like response to wind-angle change, head rotation and turn tendency.
The Effects of Curare in the Cockroach: I. dTC-Induced Failure of Leg Contraction
Authors: Friedman K. J. , Carlson A. D. 
Published: April 2021

ABSTRACT
The nature of insect curarization has been investigated in the cockroach, P. americana. Mechanical studies of leg contraction revealed that dTC, whether injected into the abdomen, injected into a leg or applied to the metathoracic ganglion, produces failure of contraction. The contraction failure caused by injecting dTC into a leg or by applying dTC to the metathoracic ganglion could be reversed by washing the drug out of the affected area. The central nervous system does not appear to be essential for curare-induced contraction failure. The contraction of metathoracic legs deprived of their metathoracic ganglion is abolished in the presence of curare. Since curare produces contraction failure when applied to the metathorax and when injected into a leg, the site of curare action must be present in both these locations. The motor nerve fibres are present in both these locations and it is proposed that contraction failure is due to the action of curare on these fibres.
The Spectral Sensitivity and Absolute Threshold of Onchidoris Fusca (Müller)
Authors: Hughes Helen P. I. 
Published: April 2021

ABSTRACT
The response of Onchidoris fusca to monochromatic light in the range 400·650 m· was measured in behaviour experiments with two opposing lights. The peak sensitivity was found to lie at 500−505 mμ. The thick, brown, dorsal skin of Onchidoris has the effect of reducing the sensitivity of the eye to ultraviolet and blue light. After allowing for a 90% absorption of light by the dorsal skin, the absolute threshold of the naked eye of Onchidoris (at 501 mμ) was found to lie between 81 and 106 quanta/sec./eye. If the lens and cornea absorb a further 10% of the available light, then each of five receptor cells in the eye of Onchidoris may be capable of responding to 12−18 quanta/sec. However, the effective threshold of the eye of Onchidoris is much higher, lying at 881−1148 quanta/sec.
The Mechanism and Efficiency of Sound Production in Mole Crickets
Authors: Bennet-Clark H. C. 
Published: April 2021

ABSTRACT
Sound production in the mole crickets Gryllotalpa vineae and G. gryllotalpa is compared with that in Gryllus campestris. In all species action of the plectrum of the left forewing on the file or pars stridens of the right wing causes the harp areas of both wings to vibrate in phase with each other. As the lateral and dorsal fields of the wing are coupled flexibly, the dorsal field resonates freely. The available muscular power of G. vineae is about 3·5 mW., of G. gryllotalpa about 1 mW., and of Gryllus about 1·2 mW. The mesothoracic musculature of Gryllotalpa is fairly similar to that of Gryllus. The calling song of G. vineae has a fundamental frequency of 3·5 kHz, a pulse length of 8 msec, and a pulse interval of 14 msec, at 16°C. The song is very pure with a second harmonic of —26 dB. Simulations of the song made with modulated oscillators are of similar purity; the song can be regarded as a modulated pure note. The sound distribution has been measured, and from the area of an isobar plot and calculation of the mean power of each pulse, the total mean sound power output is 1·2 mW. and the peak power 3 mW. The efficiency of conversion of muscular to acoustic power is about 35%. G. vineae builds a double-mouthed horn-shaped burrow for singing. This contains a bulb which probably tunes the horn to act as a resistive load to the vibrating wings. The double mouths act as a line source with directional properties which concentrate the sound in a disk above the length of the burrow. The probable advantage of a directed sound output in attracting mates is considered; the disk-shaped pattern will be better than a hemispherical pattern of similar power. G. gryllotalpa also builds a hom, but this is larger than that of G. vineae and the song frequency is far lower, at 1·6 kHz. Although the sound power is far lower, about 2·5 × 10−5 W., the horn appears to act as a resistive load to the wings. Gryllus produces only about 6 × 10−5 W. at 30°C. This is attributed to the small size and hence low radiation resistance of the wings. Estimates are made of inertial losses that occur in sound production and these are shown to account for a substantial part of the mechanical power in the systems of both G. vineae and Gryllus.
Qualitative Analysis of the Effect of Thermal Stimuli on the Spontaneous Activity of Tuberous (Knollen-) Organs in Gnathonemus Sp., Mormyridae, Pisces*
Authors: Roth Anton , Szabo Thomas 
Published: April 2021

ABSTRACT
The effect of changes in temperature on afferent nerve activity has been examined in many sense organs bearing secondary sensory cells (Sand, 1938, Hensel, 1955; Murray, 1955, 1956, 1965). In all of these investigations the thermal effect was studied in terms of the change in the number of impulses per second in the afferent nerve fibre connected to the sense organ, or more precisely to the sensory cells. It was shown that the frequency of afferent impulses changes when the temperatures at the receptor site varies, e.g. lowering the temperature (− ΔT° C.) provokes a temporary increase of frequency (‘paradoxical’ thermal effect; see Sand, 1938) and the final frequency after this temporary effect is positively correlated with the decreased temperature (−T° C.) (‘normal’ thermal effect); +Δ °T C. and +T° C. provoke opposite effects.
Differential Blood Flow Through the Afferent Branchial Arteries of the Skate, Raja Rhina*
Authors: Satchell G. H. , Hanson D. , Johansen K. 
Published: April 2021

ABSTRACT
It has been reported that in the rainbow trout, Salmo gairdneri, exercise brings about almost a fivefold increase in the transfer factor of the gills (Randall, Holeton & Stevens, 1967). Five times as much oxygen diffuses from the water to the blood per unit of concentration difference. This suggests that during exercise there is an increase in the area of the functional respiratory surface; this could be achieved if there was an increase in the ventilation and perfusion of some or all of the gills.
Observations On the Myo-Neural Physiology of A Polyclad Flatworm: Inhibitory Systems
Authors: Koopowitz H. , Ewer D. W. 
Published: April 2021

ABSTRACT
The spontaneous activity displayed by Planocera preparations decreased with repetitive electrical stimulation. It was also found that the amplitude of response was related to the time since previous spontaneous activity. The response decreased as the time interval between spontaneous activity and stimulus decreased. When a preparation was stimulated at a low frequency then there was an increase in the tone of the preparation. If the low-frequency stimulus was then followed by a stimulus at a slightly higher frequency then there was a drop in tone caused by a relaxation of the preparation. The extent of relaxation which occurred depended on parameters or the high-frequency stimulus but could be facilitated by increasing either the frequency or the duration of the initial low-frequency stimulus. Pathways involved with conduction of excitation from one side of the animal to the other pass through the brain. The brain is also required for transmission of the relaxation effect. It is concluded that these relaxation and depressant effects reflect the presence of a true inhibitory system which also shows facilitation.