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1. Activating the distal opener system (DOS), one of the conducting systems of the hydroid Tubularia, causes synchronous opening of the distal tentacles. Simultaneously recorded potentials (DOS pulses = DOSP's) from the vicinity of the responding muscles have two components: (a) an initial, short, all-or-nothing pulse reflecting activity in the conducting system, and, after a brief delay; (b) a second, slower potential thought to be a muscle action potential because its amplitude varies monotonically with that of tentacle movement. The amplitude of the second component is here used as a measure of the intensity of muscle activation.2. The second DOSP component is depressed by preceding DOS activity (defacilitation); by spontaneous tentacle movement including but not restricted to spontaneous DOS firing; by firing of the HP sytsem, one of the pacemaker systems in the polyp; and during the mouth opening associated with defecation. In all instances the first DOSP component is unchanged, indicating that the d...

Several studies have described spontaneous electrical activity in hydroids. Some of the observed pulses have common features in that they are relatively large in amplitude, on the order of several millivolts, have long duration, up to several hundred milliseconds, and may be externally recorded from large blocks of tissue. Such potentials, which are associated with simple recurrent behavioral activity, were first observed in Tubularia by Josephson (1962), in Hydra by Passano and McCullough (1962), in Obelia by Morin and Cooke (1971), in Corymorpha by Ball (1973).

Observations of the sexual reproduction of the hydroid Tubularia have been made over a period of several years in connection with my work on animal sperm chemotaxis prior to fertilization. What follows is a summary of my findings, in an attempt to add this data to the published literature on an organism which has been used almost solely for studies of asexual reproduction (Rose, 1974).

The objectives of this study were to determine the preservative effectiveness of various percentages of naphthalene-enriched creosote treatments exposed to Limnoria tripunctata attack in the laboratory and in a natural seawater environment; to determine if Limnoria attack is accelerated by exposure in the laboratory and to investigate if there are any seasonal differences in the rate of Limnoria attack in a natural environment where molluscan borers are also present. A total of 38 discs, nine treated with 10% naphthalene creosote, 10 with 28% naphthalene creosote, 10 with 30% naphthalene creosote, and nine with 40% naphthalene creosote were used. The 20% naphthalene creosote wedges showed the most resistance to Limnoria tripunctata attack in the laboratory exposures. In field exposures, all discs were heavily fouled. The dominant fouling organisms were barnacles, mainly Balanus eburneus with lesser amounts of Balanus amphitrite. Traces of hydroid (Tubularia), a few polychaetes (Nereis), and amphipods were also observed. The fouling was scraped off and the discs inspected for the presence of Limnoria tunnels and other marine borers. The discs were then resubmerged. No evidence of any other borers except Limnoria was observed on the discs. Traces of Limnoria attack were found in the field exposures in one of the 20% and one of the 40% naphthalene creosote treated discs.

Tubularia indivisa [spec. nov.] T. cylindris simplicissimis geniculatis. Raj. angl. 3. p. 31. n. 4. Adianti aurei minimi facie planta marina. Ellis corall. 31. n. 2. t. 16. f. C. Corallina tubularia calamos arundinaceos referens. Habitat in Oceano Europaeo., Published as part of Linnaeus, Carolus, 1758, Systema Naturae per regna tria naturae: secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis, Stockholm :Laurentius Salvius on page 803, DOI: 10.5962/bhl.title.542, http://zenodo.org/record/3922206

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1. Supernatant of homogenate obtained from regenerating Tubularia stems was electrophoresed through starch gel.2. Starch cores from the gel were partially inserted into the coelenterons of stems in an earlier stage of reconstitution.3. These stems were then oriented in an electric current so that any charged material in the cores would migrate toward the stems.4. The electrophoresed supernatant from primordial homogenate retarded the rate of reconstitution.5. The addition of a small amount of trypsin prior to electrophoresis removed the regeneration-inhibiting effect of the supernatant, thus indicating a polypeptide or protein nature for the inhibiting substance(s).

Tubularia [gen. nov.] Flores Hydrae. Ellis cor. t. 16. f. C. & t. 17. f. A. Stirps radicata, subgeniculata, tubulosa, membranacea., Published as part of Linnaeus, Carolus, 1758, Systema Naturae per regna tria naturae: secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis, Stockholm :Laurentius Salvius on page 803, DOI: 10.5962/bhl.title.542, http://zenodo.org/record/3922206

1. 1. Spontaneous electrical potentials can be recorded from a microelectrode in the hydranth or distal stalk of the hydroid Tubularia crocea . These potential appears as repeating single pulse and short burst of pulses. The duration of the pulse is usually about 40 msec. 2. 2. Evidence indicates the electrical potentials are due to activity in a nerve net. The patterns of activity imply that the generating it has spontaneity, feed-back and formation of patterned bursts. These properties emphasize the complexity which can be found in even a “simple” nervous system like that coelecterates. 3. 3. The most typical pattern of activity is single pulses, repeating often fairly rhythmically at a frequency of from 1/1·5 sec-1/30 sec, interrupted at regular (10 sec to several min) or irregular intervals by a burst of 3–12 pulses at a freqeuncy of about 5/sec. There is usually a post-burst-pause. Activity can appear as only single pulses, pulses and burst, or only bursis in different preparations or in the same preparation at different times. 4. 4. Single pulses are rarely and burst never restricted to one portion of the distal polyp. The conduction velocity of potentials in the upper stalk is about 42 cm/sec. Patterns of activity can be recorded from both isolated hydranths and decapitated stalks. 5. 5. Of the several types of spontaneous polyp movements. only concerted elevation of the proximal tentacles is clearlly with electrical activity. Such concerned elevation always occurred during a burst, following a burst, or following single pulses immediately after a burst. Movements of individual proximal tentacles are sometimes associated with burst, but usually have no electrical correlates. Bursts often occur with no associated tentacle movements. No correlation was found between electrical activity and movements of distal tentacles, or between single pulses other than those immediately following bursts and visible polyp behavior. Excess Mg 2+ first abolishes spontanous polyp movements, then causes a slow reduction in the amplitude fo the recorded potentials, but does not seem to affect the freqeuncy of the potentials.

Elution patterns of sperm chemo-attractants isolated from female hydroids of the genera Campanularia, Gonothyrea, Tubularia and Clava were obtained by comparative gel filtration chromatography. Generally one major and one minor peak of activity were obtained for each of the species used, except Gonothyrea which yielded two large active peaks. The Rf values of these peaks fall into two non-overlapping groups. The first group consists of the major peak obtained from Campanularia calceolifera, the first major peak from Gonothyrea and the minor peak obtained from each of the three species of Tubularia, all of which have Rf values near 0.7. The second group consists of the major peaks from the three species of Tubularia, the second major peak from Gonothyrea, the minor peak from C. calceolifera, and the major peak from Clava, all of which have Rf values near 0.5. Separation of mixtures of some of the attractants was possible using this method. Correlation between chromatographic elution position and species-specificity determined by testing the extracts from the various species against live sperm, is not perfect in all cases, in part, at least, because gel filtration is not capable of separations other than on the crude basis of molecular size. Gonothyrea and Campanularia calceolifera extracts and sperm show cross-reactivity and their active agents elute together during chromatography. The same is true for the three species of Tubularia tested. However, the second Gonothyrea peak elutes at the same position as the major peak of Tubularia activity, but these genera do not attract each other's sperm. These results suggest that methods other than chemotaxis are used by many hydroids to prevent exposure of eggs to sperm from the wrong species and that more specific separation methods will have to be used to determine the molecular basis for chemotactic specificity in hydroids.

Tubularia ramosa [spec. nov.] T. cylindris ramosis, geniculis contortis. Ellis cor. 31. n. 3. t. 16. f. A. & t. 17. f. A. Corallina tubularia gracilis & ramosa, axillis ramulorum contortis. Habitat in Oceano Europaeo., Published as part of Linnaeus, Carolus, 1758, Systema Naturae per regna tria naturae: secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis, Stockholm :Laurentius Salvius on page 804, DOI: 10.5962/bhl.title.542, http://zenodo.org/record/3922206

Stimulating the DOS, a conducting system in Tubularia, inhibits spontaneous firing of the principal pacemaker systems of the polyp, the NP and HP systems. The overall inhibition is greater the greater the stimulus frequency and there is rebound from inhibition at the end of the stimulation period. The latent period for NP inhibition is 0·4–0·6 sec and the duration of inhibition is 4–5 sec. The time course and extent of NP inhibition is independent of stimulus frequency except at high frequency where there is diminishing effectiveness of inhibition with time. HP inhibition has a similarly long latent period and even longer duration, lasting 15–20 sec. HP inhibition from successive stimuli can sum to produce a more intense effect. The behavioural significance of the inhibition seems to be to reduce spontaneous polyp movements during food capture and ingestion.

Der Temperaturkoeffizient fur die Lebensdauer vonTubularia crocea wurde fur das Temperaturintervall 36°−25° C. bestimmt. Es wurde gefunden, das derselbe etwa 2 fur einen Temperaturunterschied von 1° betragt. Das ist derselbe Temperaturkoeffizient, denLoeb fur die Lebensdauer der Seeigeleier fur das Temperaturintervall 32°−20° C. gefunden hat.

Electrical potential differences were measured in isolated stems of Tubularia during transformation of parts of the stems to hydranths. The transforming regions during the early stages of primordium formation were electronegative at the surface to adjacent non-transforming regions.Potential differences lower than those measured in regenerating stems were obtained from non-regenerating ligated stems.Ligated stems which were failing to regenerate because their potential differences were too low were given potential differences as great as those found in regenerating stems. When they were placed in an artificial field of appropriate strength, the ligated stems which regained the proper potential differences regenerated.

Of the three conducting systems known in the stalk of Tubularia—the slow system (SS), the triggering system (TS), and the distal opener system (DOS)—the SS can be eliminated as being necessarily involved in the pacemaker system inhibition seen during continued stalk stimulation because its threshold is higher than the minimal stimulus strength required for inhibition. The TS can also be eliminated as the inhibitory pathway because (1) separating a polyp from a colony and hence from a source of continued input along the TS does not result in an increase in the spontaneous activity of the polyp above that of appropriate controls, and (2) distal tentacle stimulation which activates the DOS but not the TS is more inhibitory than is stalk stimulation which excites both the TS and the DOS. The inhibitory pathway is apparently the DOS or, less likely, a yet unidentified conducting system in the stalk. Inhibitory stimulation suppresses both single pulses and bursts in the NP pacemaker system and it is likely that the HP pacemaker system is also inhibited. The greater the background level of spontaneous activity the greater is the effectiveness of inhibitory stimulation. The period of inhibition lasts for a few seconds after each stimulus.

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1. Trimethyl amine oxide, dimethyl amine and choline chloride have been isolated from the marine hydroid Tubularia larynx and identified using physical constants and spectral data. 2. The presence of two guanidine molecules has been demonstrated.

During my visit to the Plymouth Laboratory in September, 1895, Mr. Roach brought in, on the 28th, some fine colonies of Tubularia which he had found attached to the stern of a large three-masted sailing ship, the Ballachulish, of Ardrossan. This ship had come direct from Iquique, Peru, and after staying a few days in the Sound left for London. The Tubularia was kindly given to me for identification by Mr. E. J. Allen. After making drawings and noting the variation of the different organs, I came finally to the conclusion that as it agreed so closely with Parypha crocea, Agassiz, from Boston Harbour, there was no need to add another species to the genus. I was fortunate to meet with colonies of both sexes, and to find the ova in various stages of development. I believe enough material has been preserved to trace the development of the ovum, which shows a remarkable similarity to the development of the ova from the medusa of Hybocodon prolifer.Actinulæ were being liberated in large quantities when the colonies were taken from the ship, so it is possible that this hydroid may become an interesting addition to the fauna of Plymouth Sound.To distinguish this species it is necessary to examine the female gonophores, and count the number of apical ridges. Agassiz states that the number varies between six and ten, but only eight were present in my specimens. The male gonophore is destitute of ridges, and usually terminates in a blunt apex.

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La composition de l'amine acide libre dans les deux especes deTubularia a ete examinee au moyen de la chromatographie. Les tissus d'hydranthe deT. crocea avaient 21 amines acides libres dont 18 ont ete identifiees dans les hydrocauli et dans les hydranthes regeneres deT. crocea, 19 dans les hydranthes deT. spectabilis et 14 dans les hydrocauli deT. spectabilis. La difference principale entre les hydranthes et les hydrocauli reside dans la distribution de certaines taches non-identifiees qui apparurent dans les chromatogrammes developpes avec la ninhydrine et les reactifs pour les groupes des imidazoles, guanidines, ou sulfhydriles.

Recent studies of the effects of alphadinitrophenol on the higher vertebrates and man1 have shown its powerful influence on the metabolic rate. The fact that it resembles thyroxin in this respect has led to an examination of its influence on the regenerative development of certain lower invertebrates of relatively simple structure, some of whose responses to thyroxin are already known. It will be recalled that thyroxin retards the division rate of animal cells, the early development of sea urchin and ascidian2 and regeneration of the hydranth in the hydroid Pennaria.3During the past summer the effect of alphadinitrophenol in various concentrations on the regeneration of the hydroid Tubularia crocea has been observed. A single experiment will be considered at this time.Four dishes were prepared, each with 100 cc. of sea water. One served as a control. The others contained, in addition to the sea water, alphadinitrophenol in concentrations of 1:100,000, 1:200,000 and 1:400,000 respectively. In each dish wer...

only qualitative data, but is easy to carry out and requires only a few common chemicals, whereas the procedure invented by Jeuniaux must be very laborious as it requires the isolation and purification of the enzymes chitinase and chitobiase. I believe the following results obtained by the chitosan method are valid qualitatively. Hydroids. It is generally accepted that the periderm of hydroids is chitinous. Tests made on the athecate hydroid Tubularia and the thecate hydroids Obelia and Aglaop/zenia are confirmatory ; their periderm gave a good positive test. Medusae. Hydrozoan medusa Polyorchis and scyphozoan medusa Linuche dissolved in the hot alkali and hence are devoid of chitin. Velelia. The sail of this well-known chondrophore is supported by an internal plate of cartilaginous consistency which gave a good color test. Nematocysts. Pieces of the tentacles of Physalia loaded with nematocysts dissolved completely in the hot alkali, an indication that the capsular wall of the nematocysts is not chitinous as sometimes thought. Entoprocts. Barentsia zorbunai and Barentsia disoreta dissolved completely in the hot alkali, hence are devoid of chitin, in sharp contrast with the ectoprocts which are mostly highly chitinous, except cyclostomes. Cyclostomatous ectoprocts. I previously reported a negative result with the one cyclostome available, Crisia eburnea. I have now made tests on the following species : Crisia eburnea, Crisia maxima, Crisina radians, Bicrisia edwardsiens, Crisulipora occiden talis, Filicrisia francanciscana, Diaperoecia californica, and Tubulipora tuba. All were negative. Jeuniaux reported a feeble content of chitin in Crisia denticulata and attributed my negative result to the less sensitive chitosan method. In any case the chitin content of cyclotomatous estoprocts must be very small in comparison with that of other ectoprocts. Brachiopods. Pieces of the shell of Lingula including the bristles gave a strong color test as previously known. An effort was made to recover the bristles, lost in the previous test ; they are strongly chitinous. In previous tests on Discinisca the bristles also were not recovered, hence a special effort was made this time to recover them; they also gave a strong color test.

RECENTLY some colonies of a tubularian hydroid were submitted to the British Museum (Natural History) by Dr. S. Markowski. The colonies were found attached to a rope at the intake of Cliff Quay Power Station, near Ipswich, on the River Orwell in July 1959. In general appearance the colonies resembled T. larynx in having a stem height of about 5 cm.