bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Role of the Antennal Gland in the Osmotic and Ionic Regulation of Carcinus Maenas*
Authors: Riegel J. A. , Lockwood A. P. M. 
Published: April 2021

ABSTRACT
Several previous studies on various littoral and semi-terrestrial crabs [Carcinus maenas—Nagel (1934), Webb (1940); Pachygrapsus crassipes—Prosser, Green & Chow (1955), Gross (1959), Gross & Marshall (1960); Uca pugnax and U.pugiator— Green, Harsch, Barr & Prosser (1959)] have pointed out the effective role of the antennal gland in regulating the ionic concentration of the urine in sea water of various concentrations. Recently, Flemister (1958) and Green et al. (1959) have suggested that in certain of the more terrestrial crabs (Uca spp. and Gecarcinus lateralis) water may be reabsorbed from the urine. Riegel (unpublished) has obtained direct evidence of the withdrawal of water from the urine of Hemigrapsus nudus. As will be shown here, specimens of Carcinus maenas are also capable of withdrawing water from their urine in 100% sea water or in water-saturated air. In addition, specimens of C. maenas can also alter the urine/blood (hereafter designated U/B) ratios of sodium, magnesium, chloride, osmotic pressure and possibly calcium.
Central Mechanism of Hearing in Insects
Authors: Suga Nobuo , Katsuki Yasuji 
Published: April 2021

ABSTRACT
The impulses from the tympanic organ are transmitted at the prothoracic ganglion to a central neuron, the auditory T large fibre, which lies in the cord between the brain and the metathoracic ganglion. The impulses in the T large fibre are conducted rostrally and caudally with the same discharge pattern. Information is sent up to the brain, and down to the metathoracic ganglion, after a delay of about 12 msec. The impulses from the cereal hair sensilla are transmitted to two similar auditory C large fibres which lie in the cord between the metathoracic and last (6th) abdominal ganglia and are then sent up to the mesothoracic ganglia by other auditory large fibres. Central inhibitory interaction between the impulses from the tympanic nerves of the two sides are shown by a marked increase of impulses in the T large fibre following section of one of the tympanic nerves. No inhibitory interaction is found between the impulses from the two cereal nerves. The auditory T large fibre receives not only the excitatory effect from the ipsilateral tympanic nerve at the prothoracic ganglion, but also the inhibitory and weak excitatory effects from the contralateral one. The response range of the T large fibre is narrower than the threshold curve of the tympanic nerve and corresponds with one type of response range in the tympanic neurons. The response ranges of the C large fibres correspond closely with the threshold curve of the cereal nerve. A large difference in threshold between the two T large fibres is found in the response to sound incident from the side. The number of impulses in the T large fibre nearer to the sound source is greater than in that farther from the source. The difference in the number of impulses between the two T large fibres is most marked in the response to sound of the frequency which is dominant in stridulation. This difference is due to the mutual inhibitory interaction of neurons which modifies the number of impulses without changing the threshold of the tympanic large fibre. It is suggested that the central inhibitory interaction increases the information about a sound source and plays an important role in the mechanism of the directional sense. The stridulation of the group activates the tympanic nerve and evokes synchronized discharge in the T large fibre, but scarcely at all in the primary C large fibre. The tympanic organ and its neural network seem well adapted to reception of stridulation. It is concluded that though neither of the two sound receptive organs—the tympanic organ and the cereal hair sensilla—can perform frequency analysis, the insect may be able to do so by making use of both organs, since they have different frequency ranges and are served by different auditory large-fibre tracts.
The Annual Growth-Rate Cycle in Brown Trout (Salmo Trutta Linn.) and Its Cause
Authors: Swift D. R. 
Published: April 2021

ABSTRACT
A regular annual growth-rate cycle is demonstrated in wild and hatchery yearling brown trout; the fish have a high growth rate in the spring and autumn and a low growth rate during the summer and winter of each year. Experimental work with constant-environment aquaria, together with the results of the field work, indicate that the water temperature is the main external environmental factor influencing the growth rate. Maximum growth rate is achieved at 12°C. The reason for the fall in growth rate above 12°C. is discussed and it is suggested that inadequacy of the respiratory system of the fish is the prime cause.
The Urine of Gammarus Duebeni and G. Pulex
Authors: Lockwood A. P. M. 
Published: April 2021

ABSTRACT
A study has been made of the relation between blood, urine and medium concentrations in the two amphipod Crustacea G. duebeni and G. pulex. G. duebeni produces urine hypotonic to the blood but hypertonic to the medium when it is in media more dilute than 50% sea water. G. pulex forms urine which is hypotonic both to blood and medium when in 2−20% sea water. G. duebeni begins to form hypotonic urine within 2 hr. of transference from no to 160% sea water to fresh water. Hypotonic urine formation begins in these circumstances when the blood concentration is up to twice that at which hypotonic urine is formed by animals fully adapted to their medium. It is concluded (a) that the concentration of urine produced by G. duebeni is not dictated solely by the absolute level of the blood concentration; (b) that the formation of urine hypotonic to the blood in a brackish-water animal functions primarily as a means of conserving ions in the body ; (c) that the ability to regulate the concentration of the urine with rapidity will be important in an animal living in environments of fluctuating salinities.
The Efflux of Sodium Ions from the Last Abdominal Ganglion of the Cockroach, Periplaneta Americana L.
Authors: Treherne J. E. 
Published: April 2021

ABSTRACT
The rate of loss of 24Na from the terminal abdominal ganglion of Periplaneta americana L. has been studied by measuring the decline in radioactivity associated with an isolated preparation maintained in flowing physiological solution. The rate of sodium efllux was substantially reduced in the presence of 0 · 2 mM./l. dinitrophenol and in potassium-free solution. The extrusion of 24Na was not significantly affected by the removal of the fibrous and cellular sheath surrounding the ganglion. The rate-limiting process in the efflux of sodium measured in the experiments was not, therefore, the transfer of ions across the nerve sheath, but an extrusion from tissues lying at a deeper level in the central nervous system.
The Kinetics of Sodium Transfer in the Central Nervous System of the Cockroach, Periplaneta Americana L.
Authors: Treherne J. E. 
Published: April 2021

ABSTRACT
The exchange of sodium ions in the cockroach central nervous system has been studied by following the escape of 24Na from isolated abdominal nerve cords, single connectives and ganglia. Particular attention was paid to the initial rapid exchanges of sodium. The escape of sodium ions occurred as a two-stage process, an initial rapid phase eventually giving way to a slower exponential phase of sodium loss. The fast phase of efflux was not affected by the presence of 2:4-dinitrophenol, although this poison significantly reduced the second slow phase of sodium extrusion. The initial fast phase is attributed to a rapid diffusion from an extracellular space, demonstrated by 14C-inulin; the second phase is identified as the slower extrusion from the cellular components of the central nervous system.
Retinal Orientation and the Discrimination of Polarized Light by Octopuses
Authors: Rowell C. H. Fraser , Wells M. J. 
Published: April 2021

ABSTRACT
The object of the investigation was to show that the ability of Octopus to detect the plane of polarization of light does not depend upon differential reflexion from its surroundings. Animals were trained to distinguish between light plane polarized in the vertical plane (normal to the iris slit of the intact animal) and in the horizontal plane (parallel to the slit). The statocysts were then removed, abolishing the normally fixed orientation of the eyes with respect to gravity. After the operation the plane of polarization was set at each trial so as to be either normal or parallel to the iris slit. Because the eyes were now disoriented, there was no longer any constant relation between these planes and the fixed reflecting surfaces of the aquarium. The animals, nevertheless, continued to discriminate correctly. It is therefore concluded that detection of the plane of polarization depends upon some intra-ocular mechanism.
The Uptake and Distribution of Water in the Embryo of Xenopus Laevis (Daudin)
Authors: Tuft P. H. 
Published: April 2021

ABSTRACT
Water is the only constituent of the amphibian embryo that is taken up from the environment in appreciable quantities during the course of development, and at hatching it occupies nearly three times as much space in the embryo as all the other constituents combined. In spite of its small molecular size, however, and its ability to diffuse freely throughout the embryo, water is not uniformly distributed nor is its distribution constant. During the early stages of development, large liquid-filled spaces with low solid content—the blastocoel and archenteron—form between the cells, increasing and decreasing in volume as development proceeds; and although amphibian embryos normally develop in an environment which contains little or no solutes, they can tolerate a wide range of external osmotic pressures. Factors which control the uptake and distribution of water in the embryo may therefore be expected to play an important part in growth and morphogenesis. The experiments described in this paper were undertaken to obtain quantitative information on which to base a study of these factors, in the embryo of Xenopus laevis (Daudin).
The Effect of Resorbing Eggs Upon the Sex Ratio of the Offspring in Nasonia Vitripennis (Hymenoptera, Pteromalidae)
Authors: King P. E. 
Published: April 2021

ABSTRACT
Nasonia vitripeinnis is parasitic on the pupae of various muscoid flies. It has a haplo-diploid system of sex determination (Berland, 1951; Whiting, 1954), fertilized eggs producing females and unfertilized eggs males. Provided that host puparia are available continuously to the parents, the diploid females outnumber the haploid males in the ratio of 3:1. A possible mechanism for determination of this ratio has already been suggested (King, 1961). Previous work has demonstrated that the environment has a profound effect upon the sex ratio of the Hymenoptera. Clausen (1939) stated that the sex ratio varied with the sex ratio of the host, with successive generations upon the same or a different host or with different species of host, or according to whether the host population was increasing or decreasing. Chewyrew (1913), Holdaway & Smith (1932), Seyrig (1935), Taylor (1937) and Ullyet (1936) said that the proportion of males in a population depended upon the size of the host; in a small host the proportion of males was higher. Flanders (1937) working on Metaphycus stated that if the hosts were less than 1 mm. long only males were produced; the proportion of males decreased with an increase in size of the host. Whiting & Anderson (1932) working on Habrobracon, Flanders (1938) working on Tetrastichus and Wilson & Woolcock (1960) showed that the temperature affected the sex ratio.
Unit Activity in the Abdominal Nerve Cord of a Dragonfly Nymph
Authors: Fielden Ann , Hughes G. M. 
Published: April 2021

ABSTRACT
Electrical activity of single units has been studied in small bundles of nerve fibres split off from the connectives between abdominal ganglia of the dragonfly nymph. Many units showed a resting discharge but activity of other units was only found when the insect was stimulated mechanically. In some fibres the resting discharge was unaffected by mechanical stimulation and such spontaneous activity showed different patterns. These units were identified as intemeurones and a prominent feature of their discharge was an irregular firing over long periods and the formation of characteristic intermittent bursts. Responses to tactile or proprioceptive stimulation were investigated in primary sensory fibres and intemeurones. The latter showed excitatory and inhibitory effects which were often related to the site of the peripheral stimulus. Primary sensory fibres generally gave action potentials of smaller amplitude and were excited by stimulation of more localized areas. Many fibres traverse at least one connective after they enter a segmental ganglion and most ascend or descend ipsilaterally, but some crossing-over of sensory fibres occurs in the ganglia. Intemeurones were classified according to the nature of the peripheral areas from which they received their input. Ipsilateral, contralateral, and bilateral fibres have all been found but so far there is no evidence for any asymmetric fibres. Fibres responding to stimulation of a single segment or of many segments were found. Some of the latter extended over the whole length of the body and it is clear that spikes may be initiated in many of the ganglia through which an interneurone passes. It is evident from this work that a given peripheral area is represented centrally by many intemeurones and a great deal of convergence from different areas may occur on individual intemeurones.
Peripheral Reflex Inhibition in the Claw of the Crab, Carcinus Maenas (L.)
Authors: Bush B. M. H. 
Published: April 2021

ABSTRACT
Reflex opening of the claw of the crab, Carcinus maenas (or of the crayfish, Astacus pallipes), elicited by mechanical stimulation at the carpo-propodite joint, can be reflexly inhibited by stroking the inside of the claw. By electrical and mechanical recording from the opener muscle (the apodeme or motor axons of the antagonistic closer muscle being cut), and by electrical recording from the motor and inhibitor axons to this muscle, it is shown that this reflex inhibition is effected mainly peripherally, through the inhibitor axon specific to the opener muscle. Central inhibition of the motor axon plays at the most a minor part. The externally recorded action potentials of the opener muscle show strong peripheral inhibition of both the α (‘supplemented’) and β (‘simple’) forms (i.e. with and without attenuation of muscle potentials, respectively) during the reflexinhibitory stimuli, as well as sporadic attenuation at other times. Attenuation of a muscle potential results, in Carcinus claw opener, when an inhibitor impulse precedes the motor impulse by less than 15-20 msec., and is maximal when this interval is less than approximately 5 msec. Thus α inhibition predominates over β inhibition at the higher frequencies of discharge. The frequency of impulses in the opener motor axon commonly ranges from 20 to 80/sec. with brief bursts of 80-200/sec. during reflex contraction of the opener muscle, and does not fall significantly during reflex-inhibitory stimulation. The opener inhibitor, which often manifests an irregular low-frequency ‘background’ discharge during reflex opening, responds to concurrent reflex-inhibitory stimulation with a sharp increase in frequency to 100-200 impulses/sec. initially and falling to 50-100/sec. with continued reflex inhibition. Reflex-inhibitory stimulation alone elicits only inhibitor impulses. Following cessation of stimulation the tension declines ‘passively’. Owing to continuing motor activity, however, this decline is often slower than during active inhibition; it is often also erratic due to the occurrence of inhibitor impulses. When a relatively high ratio of inhibitor/motor impulse frequencies precedes a burst of motor impulses eliciting a rise in tension, the rate of this tension rise is lower than that excepted from the frequency of motor impulses evoking the rise. When there is a relatively high-frequency ‘background’ discharge in the opener inhibitor the tension in the muscle shows rapid fluctuations, whereas with lower inhibitor frequencies fairly steady tensions are sustained. This is in part because the peripheral latency of mechanical inhibition varies inversely with the ratio of inhibitor/ motor frequencies preceding the inhibition. It is suggested that a background of peripheral inhibition, by making possible quicker relaxation, may be an important factor in rapid movement.
The Mode of Action of the Corpus Cardiacum On the Hind Gut in Periplaneta Americana
Authors: Davey K. G. 
Published: April 2021

ABSTRACT
Addition of a homogenate of corpora cardiaca to the fluid bathing an isolated hind gut of Periplaneta produces an increase in tonus, amplitude, frequency and co-ordination of contractions. The corpus cardiacum acts by stimulating cells in the upper colon to release an indolalkylamine. This amine acts on the mucles through a peripheral nervous system which can function in isolation from the central nervous system.
The Composition of Haemolymph in Aquatic Insects
Authors: Sutcliffe D. W. 
Published: April 2021

ABSTRACT
Analyses were made of haemolymph obtained from aquatic representatives of nine major orders in the Insecta. In the Odonata, Plecoptera, Ephemeroptera and Hemiptera-Heteroptera, the sodium concentration is relatively high and the potassium concentration is low. The chloride concentration is relatively high, but it never exceeds the sodium concentration. In the Neuroptera, Coleoptera, Trichoptera and Diptera the sodium concentration is relatively high and the potassium concentration is low. In Nymphula nymphaeta(Lepidoptera) both the sodium and potassium concentrations are low. In all of these endopterygotes the chloride concentration is relatively low. There is no correlation between diet and the sodium/potassium ratio in haemolymph of aquatic insects. The problem of cation-anion balance is discussed. It is suggested that free amino acids contribute little to the anion pool. Bicarbonate and phosphate, largely as inorganic phosphate, contribute a small amount to the anion pool in exopterygotes. Phosphate contributes considerably more to the anion pool in some endopterygotes. Nevertheless, in all of the insects investigated, there is a deficit of anions. This deficit is usually greater in the endopterygotes. The calculated osmotic activities of the known ions and free amino acids are less than the observed osmotic activities of haemolymph. It is inferred that non-amino organic acids must be present. Preliminary investigations indicate that non-amino acids are present in the concentrations required to account for both the osmotic and the anion deficits.
The Oxygen Uptake and Metabolism of Balanus Balanus Spermatozoa
Authors: Barnes H. 
Published: April 2021

ABSTRACT
The spermatozoa of the Crustacea are often atypical, bizarre, and non-flagellated; those of the few species of cirripedes so far investigated are filamentous bodies in which a much elongated nucleus lies lateral to the fibrillar bundle over much of the length of the latter (unpublished work). When ripe spermatozoa of Balanus balanus (L.) Da Costa are teased out of a seminal vesicle into sea water, their movement is usually negligible and certainly in marked contrast to that of many other invertebrate spermatozoa. B. balanus is a hermaphrodite, yet cross-fertilization is obligatory ; the spermatozoa are transferred to the functional female in a copulatory act, after which the operculum tends to remain closed, the animal assuming a quiescent state with little cirral activity. The semen is shed in the form of a white sticky mass which at first has relatively little tendency to disperse in sea water; the semen thus tends to remain within the mantle cavity. Under natural conditions the details of fertilization are difficult to observe but it would seem that the eggs are only brought into the mantle cavity as the result of some stimulus associated with copulation.
Anaerobic Heat Production and Fructolysis of Bull Spermatozoa at Different Temperatures
Authors: Rothschild Lord 
Published: April 2021

ABSTRACT
The anaerobic heat production and fructolysis of bull spermatozoa has been measured at 37°, 27°, 17°and 7° (heat production only) C. Between 37° and 27°, 27°and 17°, and 17° and 7° C. the mean temperature coefficients of heat production were 4·07, 3·23 and 8·92 during 90 min. incubation. Between 37°and 27°, and 27° and 17° C. the mean temperature coefficients of fructolysis were 3·00 and 3·15 during 90 min. incubation. The differences between the comparable values given in (2) and (3) are not statistically significant. The temperature coefficient of the impedance change frequency of bull semen was 5·14 in one experiment and 4·17 in another. There were no impedance changes at 17°C.
The Imaginal Ecdysis of Blowflies. Evidence for A Change in the Mechanical Properties of the Cuticle at Expansion
Authors: Cottrell C. B. 
Published: April 2021

ABSTRACT
Experiments in which blowflies (with proboscis and anus blocked at emergence) were subjected to artificial pressures of 7 cm. Hg. show that expansion is possible only during the period when air-swallowing movements occur. At this time there is a change in the mechanical properties of the cuticle which is confined to the presumptive sclerite areas and enables them to expand. Before and after air-swallowing application of identical artificial pressures merely results in the temporary distension of membranous areas and in the unfolding of the wing membrane (but not the expansion of the wing veins which are presumptive sclerite areas). Prior to the cessation of air-swallowing, unfolding of the wing membranes under artificial pressure takes place without separation of the upper and lower lamellae, but after cessation, unfolding is usually accompanied by ‘bladdering’ of the wings, which become converted into blood-filled sacs.
Observations On the Myo-Neural Physiology of the Polyclad, Planocera Gilchristi
Authors: Gruber Sheila A. , Ewer D. W. 
Published: April 2021

ABSTRACT
Planocera gilchristi Jacubowa is a large polyclad worm which occurs between tide marks off the south coast of Africa. It may be kept easily in the laboratory. Our knowledge of the physiology of neuromuscular systems of the triploblastic acoelomates is meagre and Planocera appeared to be a suitable animal for experiment for its nerves may be readily seen by transmitted light, and it quickly recovers from any operative treatment.
The Cicada Song
Authors: Nakshbandi M. , Zahlan A. 
Published: April 2021

ABSTRACT
The song of the cicada (genus : Cicadatra) has been studied. The wave-form of the song shows two modes of amplitude modulation: (a) a slow modulation, period 8·3 msec; (b) a fast modulation, 40–75 μsec. growth and 185–250 μsec. decay. There is indication of wave distortion and instability at the beginning and end of the song.
Intrinsic Vasomotion in the Dogfish Gill
Authors: Satchell G. H. 
Published: April 2021

ABSTRACT
It has been reported that fish may match the extent of their respiration to their need for gaseous exchange by failing to ventilate certain gills. One third of the respiratory movements of the lamprey (Lampetra fluviatilis), when in oxygenated tap water, consist of contractions of the anterior two or three branchial chambers only. In partially deoxygenated water the anterior five and finally all of the branchial chambers become active (Wikgren, 1953). In Raja batis water is taken in through the spiracles during rest and perfuses only the anterior four gill pouches. When swimming, water enters through the mouth as well and perfuses the posterior gills (Darbishire, 1907). The dogfish Scyliorhinus canicula has a similar division of the spiracular and buccal inflows between the anterior and posterior gills (Hughes, 1960). In the eel, van Dam (1938) reports that during rest only the gills of one side may be ventilated.