bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Physiology of the Tettigoniid Ear
Authors: Lewis D. B. 
Published: April 2021

ABSTRACT
The effects of blocking the anterior and posterior tympanal slits suggests that the slits are effectively closed to spiracular sound input, but open to tympanal slit inputs. Removal of both the anterior and posterior cuticular folds significantly lowers the threshold curves for both spiracular and tympanal slit entry. The sensitivity to tympanal slit entry is increased to that of the normal spiracle. Destruction of the anterior membrane eliminates all responses in the frequency range 1–20 kHz; removal of the posterior membrane reduces sensitivity. Point-contact vibration of the three membranes at 16 kHz indicates that the central membrane is non-vibratory and that although the posterior membrane is poorly coupled to sound up to 20 kHz, its mechanical movements are transduced with less loss than those of the anterior membrane.
The Physiology of the Tettigoniid Ear
Authors: Lewis D. B. 
Published: April 2021

ABSTRACT
The threshold curve obtained for the whole organ, with a lateral sound source 30 cm from the insect, indicates the degree of interaction that occurs between the spiracular and tympanal slits inputs. The threshold curve for the whole organ with the spiracle blocked shows an increase in threshold to the level of the tympanal slits, and suggests that diffraction phenomena may be important during sound reception. Measurement of the sound intensity emitted by mechanical vibration of the tegmen shows that there is a fall in sound intensity from 124 dB at source to 54 dB at the spiracle; the spiracular intensity is still above the spiracular threshold, however.
The Physiology of the Tettigoniid Ear
Authors: Lewis D. B. 
Published: April 2021

ABSTRACT
The thresholds for the spiracle and for the tympanal slits have been determined at a variety of angles to the body axis and show little directionality. A difference in threshold levels of 20 dB exist between the ipsilateral and contralateral whole organs in the frequency range 1− 20 kHz. Single-frame exposures of a video-tape recording show that the spiracular dimensions do not change during stridulation. In the light of the evidence, a new hypothesis for acoustic orientation behaviour is advanced.
The Editors and the Journal
Authors: Parry D. A. 
Published: April 2021

ABSTRACT
Percipient users of this Journal will note that it is now no longer edited by Sir Vincent Wigglesworth and Professor J. A. Ramsay. Older readers will reflect that such changes of Editorship have been rare events: in fact, if we set aside the brief original Editorship of Professor Crew (1923–5), this is only the second editorial turn-over in the Journal’s 50 years. We hope that the new Editor, Dr J. E. Treherne, and his associates, will regard this as a good omen.
Aestivation of the African Lungfish Protopterus Aethiopicus: Cardiovascular and Respiratory Functions
Authors: Delaney R. G. , Lahiri S. , Fishman A. P. 
Published: April 2021

ABSTRACT
The present study was undertaken to elicit the temporal sequence of changes in cardiovascular and respiratory function during aestivation. Twelve lungfish (2–6 kg) equipped with ECG electrodes, arterial and buccal cannulae, were studied while aestivating in mud or in artificial cloth-bag nests. The periods of observation ranged from 0·5 to 9·5 months. The mean arterial blood pressure gradually decreased from control values of 20–28 mm Hg to a range of 14–18 mmHg during the first 30 days of aestivation, whereas the heart rate dropped more gradually (22–30 beats/min to 11–16 beats/min in 60 days). Ventilatory frequency increased 2-to 5-fold during the first 30 days of encystment and then returned to the control range (2–10 h) within 45 days. The arterial increased from control values of 25-30 mm Hg to 45-70 mmHg; arterial pH decreased concomitantly from 7·55–7·60 to 7·40–7·26 after the cocoon was formed. The arterial increased from the control range of 25·40 to 50·58 mmHg during the first 10 days and then returned to the control range. Therefore, the sequential cardiopulmonary changes during the onset of aestivation are gradual and do not parallel the decline in oxygen consumption. Aestivating lungfish also respond promptly to sensory disturbances and thus do not appear to be in a deep torpor. Aestivation is pictured as a state of dormancy, gradual in onset, and the consequence of a complicated physiological interplay.
Control of the Pacemaker System of the Nervenet in the Sea Anemone Calliactis Parasitica
Authors: McFarlane I. D. 
Published: April 2021

ABSTRACT
The rhythm of spontaneous nerve-net pulses is reset by intercalated evoked nerve-net pulses. The origin of spontaneous nerve-net pulses can shift during a burst. There seem to be many potential pacemakers, widely distributed throughout the body, but apparently absent from the tentacles. If a spontaneous or evoked pulse in the endodermal slow conduction system (SS 2) occurs during a burst, the nerve-net pulse intervals are increased during a 15–30 sec period following the SS 2 pulse. Additional SS 2 pulses cause a further increase in pulse intervals. Nerve-net bursts are followed by a sequence of muscular contractions. The size of the contraction shown by any muscle group depends on nerve-net pulse number and frequency, the optimum frequency being different for different muscles. It is suggested that the SS 2 pulse action on nerve-net pulse frequency can significantly alter the behavioural output of nerve-net bursts. The SS 2 activity may represent sensory feedback on to the nervous pacemakers.
Vascular Anatomy of the Counter-Current Heat Exchanger of Skipjack Tuna*
Authors: Stevens E. Don , Lam How Man , Kendall J. 
Published: April 2021

ABSTRACT
The anatomy of the counter-current heat exchanger of skipjack tuna is described and the pattern of blood flow is analysed. The pattern of blood flow is from the dorsal aorta, through the exchanger to segmental arteries to the tissues, from the tissues to segmental veins and back through the exchanger to the post-cardinal vein. The vessels in the exchanger are about the same size as systemic arterioles and venules and are about 10 mm long. There are about 125000 of each type in a 2 kg tuna. The velocity of blood flow in the exchanger is about i/8oth of that in the dorsal aorta and post-cardinal vein allowing time for heat transfer. There are many valves in the segmental veins which may be expected because of the resistance offered by the exchanger. The vessels in the tuna heat exchanger are an order of magnitude larger than those in the swim-bladder rete, thus permitting heat transfer but preventing gas transfer.
The Significance of Some Spectral Features in Mating Call Recognition in the Green Treefrog (Hyla Cinerea)
Authors: Gerhardt H. Carl 
Published: April 2021

ABSTRACT
Synthetic calls with a waveform periodicity of 300/sec and a bimodal spectrum attracted female green treefrogs as effectively as natural calls. Effectiveness was markedly reduced if the relative amplitude of the two spectral peaks differed by as little as 10 dB. Optimal frequency bands were 900-1100 Hz in the low range and 2700-3300 Hz in the high. Addition of components at 1800 and 2100 Hz rendered the call less attractive. In the absence of a bimodal stimulus, most females responded to a call containing a single spectral peak in the high or low range. Mating call recognition in the green treefrog is compared with that in the bullfrog.
Aspects of Ionic Transport Mechanisms in Crayfish Astacus Leptodactylus
Authors: Ehrenfeld J. 
Published: April 2021

ABSTRACT
During the uptake of chloride from an external choline chloride solution, electroneutrality appears to be preserved by excretion of base, but base excretion independent of chloride absorption also occurs. Sodium ion uptake from sodium sulphate solutions is compensated by excretion of hydrogen ions, but this has been established only in animals adapted to distilled water. In animals preadapted to running water, the sodium ion influx can be abolished almost totally by amiloride without diminishing ammonium excretion. The net fluxes of sodium and chloride are inhibited by acetazolamide and cyanide. These results are interpreted as indicating that Na+ and Cl− are absorbed chiefly in exchange for H+ and HCO3−, and are discussed in relation to an exchange diffusion mechanism.
Neurophysiological Studies On Echolocation Systems in Awake Bats Producing CF-FM Orientation Sounds
Authors: Suga N. , Simmons J. A. , Shimozawa T. 
Published: April 2021

ABSTRACT
The bats Pteronotus parnelli, P. suapurensis and Noctilio leporinus emit orientation sounds first containing a constant-frequency (CF) and then a frequency-modulated (FM) component. P. parnellii produced a long CF with a second harmonic at 62 kHz to which its auditory system was sharply tuned. In the other two species, the CF was shorter and there was no sharp tuning. Electrical stimulation of the midbrain reticular formation and/or the central grey matter elicited vocalizations which were indistinguishable from those used for echolocation. The electrically-elicited vocalization was enhanced by acoustic stimuli. In P. parnellii, this vocal response was sharply tuned at 62–63 kHz and also to downward sweeping FM sounds. In P. suapurensis and N. leporinus, the vocal responses were prominent only to downward sweeping FM sounds. This indicates that the FM is important to echolocation in all these bats and that the CF component is more essential to echolocation in P. parnellii than to that in P. suapurensis and N. leporinus. The responses of primary auditory neurons to the onset and cessation of pure tone stimuli were due to mechanical events, not due to a rebound from neural inhibition. Masking experiments with P. parnellii indicate that the neural response at the cessation of a CF-FM sound similar to its orientation sound mainly consisted of the response to the FM component and not the off-response to the CF component. During vocalization, self-stimulation was reduced by contraction of middle-ear muscles. This was not due to the acoustic reflex which started to occur with a 6 msec latency.
Calcium-Dependence of Neurosecretion by Exocytosis
Authors: Normann Tom Christian 
Published: April 2021

ABSTRACT
Exocytosis of neurosecretory granules in the corpus cardiacum of the blowfly Calliphora erythrocephala was induced both by electrical stimulation and by depolarization with K+. This secretory activity was quantitatively determined by the frequency of omega figures and vesicle clusters, which are the ultrastructural indications of two distinct phases of the exocytotic process. Experimentally elicited exocytosis was reduced when Ca2+ were omitted from the bathing medium. This result supports the idea that the coupling between excitation (depolarization) and exocytosis involves Ca2+ influx through the axolemma. Barium effectively substitutes for calcium in the secretory process. High levels of magnesium in the bathing medium, however, decreased exocytosis, possibly by interfering with calcium influx.
Experimental Studies on the Circulatory System of the Late Chick Embryo
Authors: White Peter T. 
Published: April 2021

ABSTRACT
A method of preparing the 15/17-day chick embryo for physiological studies is described and the results of an investigation of flow patterns in the circulatory system using oxygen determinations and dye injections is reported. A considerable separation of deoxygenated and oxygenated blood streams occurs in the incompletely divided heart such that a large part of the oxygenated stream flows through the perforated interatrial septum to the left heart for distribution to head, neck, thorax and heart. A mechanism also exists whereby the gut and yolk sac receive blood at an oxygen saturation greater than the remainder of the posterior body. Some quantitative estimates of blood and oxygen flows are made and the circulatory system of the late chick embryo is compared with that of the foetal mammal.
Interneurones in Crab Connectives (Carcinus Maenas (L.)): Directional Statocyst Fibres
Authors: Fraser Peter J. 
Published: April 2021

ABSTRACT
Five interneurones in each connective respond directionally to rotation of a crab. Each seems to be activated by one direction of fluid flow in one statocyst canal. The anatomy of two is known and correlates well with a direct input from the receptors of one statocyst. Three of the fibres have input from leg joint proprioceptors.
The swimming reflex and a complicated turning reflex are evoked on rotation of a minimally restrained crab. It is likely that the statocyst interneurones are involved in these and other behaviour patterns, including the rearing reflex and sideways walking.
Interactions Between Neurones Mediating Tuft Withdrawal in Tritonia Hombergi
Authors: Dorsett D. A. , Willows A. O. D. 
Published: April 2021

ABSTRACT
The seven neurones that command the three stages of branchial tuft withdrawal interact by electrotonic and chemically mediated polysynaptic pathways.
The pleural tuft retractors, L and R Pl 6, make electrotonic synapses with the ipsilateral neurones Pd 2, which cause retraction of the tips of the tufts.
The chemically transmitting pathways, between these and other retractor neurones, are mostly reciprocal and can be classified as weak or strong. The former are small in amplitude, with long latencies (1–3 sec) and are labile to repeated activation; the latter are of large amplitude and shorter latency (0·5–0·8 sec), but may still show decrement with repeated use. Frequently the p.s.p. shows indications of 1:1 correlation with the spike pattern in the driven neurone, but the long latencies require the presence of at least one interneurone in the pathway.
The progressive spread of the behavioural response (withdrawal of the tips, complete unilateral withdrawal, complete bilateral withdrawal of all tufts), which occurs with increasing stimulus intensity, is not dependent on a central hierarchy in the activation of the tuft retractor neurones. Reciprocal feedback leads to a general increase in central excitability, the threshold for more extensive responses being probably determined largely by the sensory input to individual neurones.
The unique pleural cell R Pl 5 is exceptional, both in the variety of motor activity it commands and in the absence of reciprocal connexions from other retractor neurones.
A Method for Determining Total Carbon Dioxide in Nanolitre Volumes of Liquid
Authors: Little Colin 
Published: April 2021

ABSTRACT
A microdiffusion method is described by which total carbon dioxide can be determined in 2 nl samples of liquid. The standard deviation for 0–30 mm/1 HCO3− is approximately 1 mm/1. The volume of sample can be reduced to o·8 nl, but the S.D. then rises to 1·6 mm/1. With volumes of 0·4 nl, the S.D. is 2·7 mm/1. It is not possible, without modification, to use volumes smaller than about 0·4 nl. In samples where the HCO3− concentration is low, accuracy can be increased by using larger volumes: 10 mm/1 HCO3− can be determined in 6 nl samples with a standard deviation of 0·5 HIM/1.
Pharmacological Induction of Plasticization in the Abdominal Cuticle of Rhodnius
Authors: Reynolds Stuart E. 
Published: April 2021

ABSTRACT
Injections of 5-hydroxytryptamine (5-HT, serotonin) are found to cause plasticization of the abdominal cuticle of Rhodnius larvae. This plasticization is a direct action of 5-HT on some element in the body wall; the central nervous system is not required. It is probable that 5-HT acts directly at a receptor on the epidermal cells. The relationship between structure and plasticizing activity for a number of 5-HT analogues has been investigated. The receptor resembles other ‘classical’ 5-HT receptors in its requirements, but is unlike the 5-HT/diuretic hormone receptor of Rhodnius Malpighian tubules.
Magnesium Regulation in Mosquito Larvae (Aedes Campestris) Living in Waters of High MgSO4 Content
Authors: Kiceniuk J. , Phillips J. E. 
Published: April 2021

ABSTRACT
Although larvae of A. campestris can live in natural waters in which the magnesium content may vary seasonally from extremes of 1 to more than 100 mm, the haemolymph levels of magnesium vary only from 1·5 to 4 mm. Larvae survive in water containing 90 mm-Mg and drink their own body weight every few hours, the ingested fluid and the magnesium ions being largely absorbed into the haemolymph via the midgut. The urinary concentration of Mg2+ ions was always substantially higher than that of the external media and up to 23 times that of the haemolymph. It is suggested that magnesium is not excreted across the general body surface, the Malpighian tubules and hindgut being largely responsible for removing magnesium from the haemolymph. These physiological observations are discussed in relation to the environmental conditions under which larvae are naturally found.
Efferent Regulation of the Abdominal Stretch Receptors of the Crayfish
Authors: Ilyinsky O. B. , Spivachenko D. L. , Shtirbu E. I. 
Published: April 2021

ABSTRACT
Efferent regulation of the activities of the slowly adapting and fast adapting stretch receptors (the MRO1 and MRO2, respectively) of Astacus fiuviatilis was studied. It was shown that the receptors activity is under the efferent control of two central inhibitory neurones: the main inhibitory neurone (MIN) and the accessory neurone (AIN). Their activities were determined by the degree of discharge from the receptors. There was close interaction between the MRO1 and the MIN. The activity of the MIN was determined by the activity of the MRO1 to a higher degree than vice versa; the activity of the MIN was influenced not only by the MRO1 impulses, but by the cessation of those impulses as well (silent periods). The MRO1 could inhibit or excite the MIN, whereas the MIN could inhibit the activity of the MRO1. Interaction between the MRO1 and the MIN could occur during background activity of the MRO1 or of the MIN. In both cases the activity of the initially non-active neurone appeared only after stimulation had been applied to the MRO1. Often each impulse of the MRO1 resulted in a MIN discharge of from 1 to 361 impulses. Sometimes the responses appeared after burst-discharges, induced by mechanical stimulation, of the otherwise inactive MRO1. During interaction between the MRO1 and the MIN, the neurone commencing activity had a higher discharge frequency, if only by 1–2 imp./ sec, than the one firing previously. Under the influence of MIN impulses the response of the MRO1 to stimulation changes from slowly adapting to fast-adapting. The MIN has a slight inhibitory effect on the activity of the MRO2 which is most clearly seen in the course of background activity of the MRO2. The MRO2, however, does not exert much influence on the activity of the MIN. The AIN had much less effect than the MIN on receptors, and the receptors did not naturally evoke AIN impulses. There is, therefore, apparently a more complicated connexion between the receptors and the AIN than between the receptors and the MIN.
Role of active potassium transport by integumentary epithelium in secretion of larval-pupal moulting fluid during silkmoth development
Authors: Jungreis A. M. , Harvey W. R. 
Published: April 2021

ABSTRACT
The exuvial side of the pharate pupal integument is usually positive to the haemolymph-side, both in vivo and in vitro, during the period when the moulting fluid is being secreted. The ratio of potassium flux toward the exuvial space is higher than that toward the haemolymph, under both open-circuit conditions and short-circuit conditions, demonstrating by the Flux Ratio test that potassium is actively transported across the isolated integument during this secretion period. Just prior to ecdysis, while moulting fluid is being reabsorbed, the potassium flux ratios become unity, suggesting that active potassium transport has ceased, but the short-circuit current that remains suggests that some other ion is actively transported at this time. We argue that the potassium salt solution, formed in the exuvial space (as water presumably follows the actively transported potassium), has three functions (1) to accomplish the gel-sol transformation, (2) to activate the gel enzymes and (3) to buffer the enzyme solution at a pH favourable to the activity of the gel enzymes.
Active Transport of Sulphate Ions by the Malpighian Tubules of Larvae of the Mosquito Aedes Campestris
Authors: Maddrell S. H. P. , Phillips J. E. 
Published: April 2021

ABSTRACT
Larvae of Aedes campestris ingest and absorb into their haemolymph large quantities of the sulphate-rich water in which they live, yet they are able to maintain the sulphate content of the haemolymph well below that of the environment. Tracer experiments showed that sulphate regulation was not achieved by deposition of precipitates in the tissues. In vitro preparations of Malpighian tubules secrete sulphate ions actively against both a three times concentration gradient and an electrical potential difference of 20 mV. This transport is half saturated at about 10 mm. The rate of sulphate secretion by the Malpighian tubules is sufficient to remove all of the sulphate ingested by larvae living in waters which contain less than 100 mm of this anion. At higher concentrations, sulphate ions are probably also excreted elsewhere, perhaps by the rectum or anal papillae.
Electrophysiology and Co-ordinated Behavioural Responses in the Colonial Bryozoan Membranipora Membranacea (L.)
Authors: Thorpe J. P. , Shelton G. A. B. , Laverack M. S. 
Published: April 2021

ABSTRACT
There is a colonial retraction response in the Bryozoans Membranipora membranacea and Electra pilosa. The conduction velocity of the response is about 100 cm sec−1. The colonial response will circumnavigate the end of a cut, but will not cross it. The lophophore retraction time is 60–80 msec. The lophophore retractor muscle with a peak contraction rate of 20 + muscle lengths per second is probably one of the fastest contracting muscles known. The colonial responses to successive stimuli under certain circumstances are similar to those of some corals. Nervous pulses can be recorded travelling across the colony at the same velocity as the colonial response. Increases and decreases in the number and frequency of T1 pulses correspond with increases and decreases in the area and duration of the colonial response and are produced in response to the same stimuli. Other pulses can be recorded which correspond to the retraction of the lophophore retractor muscle. The lophophore retractor muscle is apparently under the control of a giant axon from the zooidal ganglion. The colonial nervous system has many of the properties expected of a nerve plexus.
Sperm concentration and fertilization rate in Bufo arenarum (Amphibia: Anura)
Authors: Cabada M. O. 
Published: April 2021

ABSTRACT
The influence of sperm concentration upon the fertilization rate of Bufo arenarum oocytes was determinated. The experimental results were analysed according to the theories of Rothschild and Swann, and Hultin and Hagström for Psammechinus miliaris. The experimental results agreed with the predictions of the latter theory. Since Bufo arenarum and Psammechinus miliaris oocytes differ in both size and disposition of jelly envelopes, the postulations of Hultin and Hagström’s theory appear to have a general validity.