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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Growth, bioenergetics and life-span of Octopus cyanea and Octopus maya

Van Heukelem, William F 08 1900 (has links)
The objectives of the work undertaken were to: (1) rear Octopus cyanea and Octopus maya through all stages of the life cycle in the laboratory; (2) measure growth rates; (3) determine energy budgets; (4) examine the effects of temperature, size and age on food intake, growth, metabolism and conversion efficiency; and (5) determine life-spans of the two species. Attempts to rear O. cyanea through the planktonic stage were unsuccessful and data were obtained on feral animals in the laboratory. O. maya was reared through four generations from eggs collected at Campeche, Mexico. Animals were fed ad libitum on living crabs. Weights were recorded at I5-day intervals and food intake was quantified. Dry matter, ash and caloric content of crab and O. cyanea samples were determined. Animals grew exponentially for the first third of their benthic life, doubling their weight every 11-13 days at 22 - 27 degrees C. The exponential growth phase was followed by a period of logarithmic growth which terminated at full sexual maturity. Average maximum sizes attained by the two species were comparable (3.2 kg for O. maya and 3.6 kg for O. cyanea). O. cyanea settles from the plankton at an estimated weight of 0.3 g and attains maximum size about 10.5 months later. O. maya hatched as benthic juveniles weighing 0.1 g and grew to maximum size in about 8.5 months. Maximum size attained by both species varied from several hundred grams to several kilograms depending on food availability. Assimilation efficiency of O. cyanea was very high (95%) and independent of animal size and food ration size. Gross growth efficiency of both species averaged about 40% on a wet weight basis and was independent of size (old animals excluded) and temperature. The relationship between food intake and growth was linear in both species and showed no sign of decrease at high ration level. Material budgets indicated that on a wet weight basis, 40% of ingested food was used in growth, 55% in maintenance and 5% was not absorbed. Energy budgets on a caloric basis indicated that 60% of ingested energy was used in growth, 36% in total metabolism and 4% voided as feces. Rates of food intake, growth and metabolism were about twice as high at 30 as at 20 degrees C. Females of both species died after brooding their eggs and males died at about the same age. O. cyanea had a lifespan of 12-15 months from settlement and O. maya lived an average of 10 months from hatching in the laboratory. Low light intensity and elevated temperature in the laboratory were thought to produce early spawning and hence short life-spans in laboratory animals. A theory is presented to explain large variations in size at spawning and lack of seasonality. Growth, differentiation, maturation and spawning are viewed as programmed events in the life cycle. Light, temperature and food determine the rate at which the program runs and hence size and age at spawning. Senescence and death are viewed as events occurring after the program is completed.
2

Molecular phylogenetics and the evolutionary history of reproductive strategies in benthic shallow-water octopuses (Cephalopoda: Octopodinae) /

Guzik, Michelle Tanya. January 2004 (has links)
Thesis (Ph.D.) - James Cook University, 2004. / Typescript (photocopy). Appendices : leaves 139-147. Bibliography: leaves 111-138.
3

Octopus insularis: descrição de desova e paralarvas recém-eclodidas, cultivo de sub-adultos em diferentes sistemas e aspectos da fisiologia digestória de animais selvagens e cultivados

Borges, David Araújo January 2013 (has links)
BORGES, D. A. Octopus insularis: descrição de desova e paralarvas recém-eclodidas, cultivo de sub-adultos em diferentes sistemas e aspectos da fisiologia digestória de animais selvagens e cultivados. 2013. 119 f. Tese (doutorado) - Universidade Federal do Ceará, Instituto de Ciências do Mar, Programa de Pós-Graduação em Ciências Marinhas Tropicais, Fortaleza-CE, 2013. / Submitted by Nadsa Cid (nadsa@ufc.br) on 2014-07-25T18:11:30Z No. of bitstreams: 1 2013_tese_daborges.pdf: 3693680 bytes, checksum: ba62b252aa912735d6d72a807d22a24a (MD5) / Approved for entry into archive by Nadsa Cid(nadsa@ufc.br) on 2014-07-25T18:14:14Z (GMT) No. of bitstreams: 1 2013_tese_daborges.pdf: 3693680 bytes, checksum: ba62b252aa912735d6d72a807d22a24a (MD5) / Made available in DSpace on 2014-07-25T18:14:14Z (GMT). No. of bitstreams: 1 2013_tese_daborges.pdf: 3693680 bytes, checksum: ba62b252aa912735d6d72a807d22a24a (MD5) Previous issue date: 2013 / From cephalops, octopuses are considered economically interesting species for aquaculture. Their fishery has been steadily decreasing since 1990’s, which has led to increase in the demand for octopuses. In 2006 researchers have found in the Brazilian northeast coast a kind of octopus initially identified as Octopus vulgaris, and later, in 2008, identified as Octopus insularis. In chapter 01 of this thesis was describe newly-hatched paralarvae of Octopus insularis and defined its first life habit as planktonic with a positive phototaxis and no lecitotrófica phase. It has been determined that the time between the onset of spawning and hatching is approximately 25 days. It was found that the O. insularis lay their eggs in clusters with an average density of 390eggs/cm and no egg size variance was observed due to variation in female’s size. For chapter 02 was developed a laboratory system with closed recirculating water for food preference and grow out experiments with O. insularis sub-adults. For the first test, the double choice food, acrylics “Y” were used. The foods tested were crab (Callinectes bocourti) gastropod (Stramonita brasiliensis) and sardines (Sardinella spp), all tested paired. We observed the capture of all foods, however there was a clear preference of crab and fish across the gastropod. Even observing a higher crab frequency capture, no significant difference was observed between the frequency of catching crab and fish. Later we tested the grow out of O. insularis sub-adults at 23 and 28°C using crab as food. For all ongrowing indices used, grow out at 28°C show higher values than at 23°C. A total weight gain (ΔW) of 309.8g, a relative weight gain (GR) of 100.9%, an absolute growth rate (AGR) of 9.4g/day and a specific growth rate (SGR) of 2.1%BW/day were registered for 28°C test. Even with a higher food intake by the 28°C cultured group, there was no difference between the feed conversion rate (FCA) between groups cultured at 23 and 28°C. It was also accomplished the O. insularis sub-adults grow out in floating cages being offered different proportions of crabs and fish as food. It was observed a higher growth by the animals feed exclusively by crabs, and this test shown an AGR of 13.6g/day, and a SGR of 1.4%BW/day. There were no significant difference in the growth rates of the groups fed only fish and fed 50% fish and 50% crab. In chapter 03 were analyzed some of the digestive enzymes of the digestive tract of wild and cultured O. insularis species. For the total alkaline protease activity was observed greater activity in the posterior salivary gland (GSP) in wild individuals. For total acidic proteolytic activity no significant difference between the wild and cultured group was observed. Significant activity was only observed in the digestive gland (GD). Trypsin activity was observed in GD and GSP for both groups, wild and cultured, although cultured xi group have shown much lower activity them wild group. For chymotrypsin activity, activities were observed in the intestine (INTEST) and GSP for both analyzed groups, however wild group presented higher values of enzyme activity. Analyzing the aminopeptidases activity for 9 different amino acids, it was found a greater activity, for most of analyzed amino acids, in wild group than cultured group. There is also a strong relationship between these aminopeptidases that occur in the wild group GSP and muscle composition of animals from this same group. For amylase activity, was observed a high activity in various organ of the digestive tract, specifically the anterior salivary gland (GSA), GSP, cecum (CEC), GD and INTEST, and again wild group shown a higher activity than culture group. / Dentre os cefalópodes os polvos são considerados espécies de grande interesse econômico para a aquicultura. Sua pesca vem decrescendo gradualmente desde os anos 1990, o que levou a um aumento na demanda por polvos. Em 2006 pesquisadores encontraram na costa do nordeste do Brasil uma espécie de polvo inicialmente identificada como o Octopus vulgaris, e posteriormente, em 2008, identificado como Octopus insularis. No capitulo 01 desse trabalho foi realizado a descrição de paralarvas recém-eclodidas de O. insularis sendo definido seu hábito de vida inicial como planctônico com fototaxia positiva e ausência de fase lecitotrófica. Foi determinado que o tempo entre o início da desova e a eclosão dos ovos é de aproximadamente 25 dias. Identificou-se que o O. insularis põem seus ovos em cachos com uma densidade média de 390 ovos/cm de cacho e não foi verificado variação do tamanho dos ovos em virtude da variação do tamanho das fêmeas. Para o capítulo 02 foi desenvolvido toda uma estrutura laboratorial com sistema fechado de recirculação de água para a realização dos testes de predileção de alimento bem como para os testes de engorda do O. insularis. Inicialmente foi realizado o teste de dupla escolha de alimento com sub-adultos de O. insularis utilizando “Y” de acrílico. Os alimentos testados foram siri (Callinectes bocourti) gastrópode (Stramonita brasiliensis) e sardinha (Sardinella spp), sendo todos testados dois a dois. Observou-se a captura de todos os alimentos, contudo houve uma clara predileção do siri e do peixe frente ao gastrópode. Mesmo observando-se uma maior frequência de captura dos animais pelo alimento siri, não foi verificado uma diferença significativa entre a frequência de captura do siri e do peixe. Posteriormente realizou-se o cultivo de sub-adultos do O. insularis a 23 e 28°C sendo utilizado siri como alimento. Para todos os índices de crescimento utilizados, o cultivo a 28°C foi superior ao a 23°C sendo observado para 28°C um ganho de peso total (ΔW) de 309,8g, um ganho de peso relativo (GR) de 100,9%, uma taxa de crescimento absoluta (AGR) de 9,4g/dia e uma taxa de crescimento específica (SGR) de 2,1%BW/dia. Mesmo havendo uma maior ingestão de alimento pelo grupo cultivado a 28°C não se observou diferença significativa entre o fator de conversão alimentar (FCA) entre os grupos cultivados a 23 e 28°C. Foi realizado também o cultivo de sub-adultos do O. insularis em gaiolas flutuantes sendo ofertado diferentes proporções de siri e peixe na alimentação dos indivíduos. Observou-se um maior crescimento dos animais alimentados apenas com siri sendo obtidos valores de AGR de 13,6g/dia e SGR de 1,4%BW/dia. Não foi observada diferença significativa para os índices de crescimento dos grupos alimentados apenas com ix peixe e alimentados com 50% de peixe e 50% de siri. Durante o capítulo 03 foram analisadas algumas das enzimas digestivas do trato digestório de animais selvagens e cultivados da espécie O. insularis. Para a atividade proteolítica alcalina total observou-se uma maior atividade na glândula salivar posterior (GSP) em indivíduos selvagens. Para a atividade proteolítica total ácida não foi observada diferença significativa entre o grupo selvagem e cultivado, sendo observada atividade significativa apenas na glândula digestiva (GD). A atividade de tripsina foi observada na GD e GSP dos dois grupos tenso o grupo cultivado apresentado valores bem mais baixos de atividade que o grupo selvagem. Para a atividade de quimotripsina foram observadas atividades na GSP e intestino (INTEST) dos dois grupos analisados tendo o grupo selvagem apresentado maiores valores de atividade enzimática. Ao analisar a atividade de aminopeptidases referente a 9 diferentes aminoácidos verificou-se que para a maioria desses aminoácidos houve uma maior atividade do grupo selvagem frente ao grupo cultivado. Verificou-se também uma forte relação dessas aminopeptidades que ocorrem na GSP de animais do grupo selvagem com a composição do musculo desses animais. Quanto a atividade de amilase foi observado uma elevada atividade em vários órgão do trato digestório, marcadamente a glândula salivar anterior (GSA), GSP, ceco (CEC), GD e INTEST, sendo novamente presenciada uma maior atividade por parte do grupo selvagem.
4

Proteínas de tintas de moluscos marinhos composição, função e mecanismo de ação

Tavares, Tallita Cruz Lopes January 2010 (has links)
TAVARES, Tallita Cruz Lopes. Proteínas de tintas de moluscos marinhos: composição, função e mecanismo de ação. 2010. 70 f. Dissertação (Mestrado em Ciêncais Marinhas Tropicais) - Instituto de Ciêncais do Mar, Universidade Federal do Ceará, Fortaleza, 2010. / Submitted by Nadsa Cid (nadsa@ufc.br) on 2012-02-01T18:04:42Z No. of bitstreams: 1 2010_dis_tclopes.pdf: 4775265 bytes, checksum: 9c6bb791c4e247cf3a10c23974ad9971 (MD5) / Approved for entry into archive by Nadsa Cid(nadsa@ufc.br) on 2012-02-02T14:00:06Z (GMT) No. of bitstreams: 1 2010_dis_tclopes.pdf: 4775265 bytes, checksum: 9c6bb791c4e247cf3a10c23974ad9971 (MD5) / Made available in DSpace on 2012-02-02T14:00:06Z (GMT). No. of bitstreams: 1 2010_dis_tclopes.pdf: 4775265 bytes, checksum: 9c6bb791c4e247cf3a10c23974ad9971 (MD5) Previous issue date: 2010 / In shelled molluscs or those in which it is present as vestigial as cephalopods and gastropods opistobrânquios, the lack of external protection led to the evolution of defense mechanisms dominated by the secretion or incorporation of bioactive chemicals. Proteins synthesized again are good examples of these molecules, were found in paints of various species of sea slugs, particularly the genus Aplysia. Many have already revealed belong to protein families with oxidástica activity of L-amino acids (LAAOs), a group which comprises also bioactive proteins found in snake venoms. The characterization therefore biological activities and biochemical profile of these proteins is very useful for us to understand how to give the defense mechanisms of animals and how widespread they are, in addition to providing subsidies to its application biomedicinal. This study aimed to elucidate the mechanisms of action of P-dactilomelina, antibacterial protein purified from Aplysia ink dactylomela, and comparison of protein composition and antimicrobial activities of paint released by two gastropods, A. dactylomela and Bursatella leachii, and a cephalopod, Octopus sp .. The study revealed that dactilomelina-P is an L-amino acid oxidase capable of oxidizing L-lysine and L-arginine, with a higher affinity for L-arginine, with a Km of 0.22 + - 0.16 mM / L for L -lys and 0.015 + - 0.01 mM / L L-arg. It also demonstrated that its antibacterial activity is measured by this property, with the hydrogen peroxide generated in the oxidation enzimáticca, great aprtipação in bacterial inhibition. The protein behaves in a non-bacteriostatic when supplemented with L-lysine and L-angilina, being in the presence of bactericidal. In addition, the antibacterial activity was shown to be dependent on the concentration of amino acids available for oxidation by the protein. Staphylococcus aureus activity must occur through mechanisms that do not induce damage to cell morphology, since we did not observe any morphological change by atomic force microscopy. The analysis of the three pro paint SDS-PAGE revealed the presence in them all, protein bands of about 60 kDa, and bands of lower molecular weight. For Western blot can observe the existence of immunologic identity between proteins of the three dyes, since polyclonal antibodies produced against P-dactilomelina recognized protein (s) of about 60 kDa in ink B. leachii and approximately 30 kDa in ink Octopus sp. Among the three dyes, only the ink of A. dactylomela showed antibacterial and antifungal activities / Nos moluscos sem concha ou naqueles em que a mesma estão presente na forma vestigial, como cefaóipedes e gastrópodes opistobrânquios, a falta dessa proteção externa conduziu à evolução de mecanismos de defesa dominados pela secreção ou incorporação de substâncias químicas bioativas. Proteínas sintetizadas de novo são bons exemplos dessas moléculas, tendo sido encontradas nas tintas de várias espécies de lesmas do mar, particularmente do gênero Aplysia. Muitas já revelaram pertencer a famílias de proteínas com atividade oxidástica de L-aminoácidos (LAAOs), grupo do qual fazem parte também proteínas bioativas encontradas nos venenos de serpentes. A caracterização, portanto, das atividades biológicas e do perfil bioquímico dessas proteí­nas é muito útil para que possamos entender como se dão os mecanismos defensivos desses animais e quão difundidos esses são, além de proporcionar subsí­dios para sua aplicação biomedicinal. Esse estudo visou a elucidação dos mecanismos de ação da dactilomelina-P, proteína antibacteriana purificada da tinta de Aplysia dactylomela, e a comparação da composição protéica e das atividades antimicrobianas das tintas liberadas por dois gastrópodes, A. dactylomela e Bursatella leachii, e por um cefalópode, Octopus sp.. O estudo revelou que a dactilomelina-P é uma L-aminoácido oxidase capaz de oxidar L-lisina e L-arginina, com maior afinidade por L- arginina, com Km de 0,22 +- 0,16 mM/L para a L-lys e de 0,015 +- 0,01 Mm/L para a L-arg. Demonstrou também que sua atividade antibacteriana à medida por esta propriedade, tendo o perôxido de hidrogênio, gerado na oxidação enzimática, grande partipação na inibição bacteriana. A proteína se comporta de maneira bacteriostítica quando em meio não suplementado com L-lisina e L-angilina, sendo bactericida na presenãa destes. Além disso, a atividade antibacteriana mostrou ser dependente da concentração de aminoácidos disponibilizados para oxidação pela proteína. A atividade Staphylococcus aureus deve ocorrer por meio de mecanismos que não induzam danoso na morfologia celular, uma vez que não foi observada qualquer alteração morfológica por microscopia de força atômica. Já a análise das três tintas pro PAGE-SDS revelou a presença, em todas elas, de bandas protéicas de cerca de 60 kDa, além de bandas de peso moleculares mais baixos. Por Western blot pode-se observar a existência de identidade imunológica entre proteinas das três tintas, visto que anticorpos policlonais produzidos contra a dactilomelina-P reconheceram proteína(s) de cerca de 60 kDa na tinta de B. leachii e de cerca de 30 kDa na tinta de Octopus sp. Dentre as três tintas, somente a tinta de A. dactylomela apresentou atividades antibacterianas e antifúngica
5

Skin patterning in the octopus Eledone cirrhosa : a morphological and functional approach

Dubas, Françoise January 1982 (has links)
The aim of this thesis is to investigate the peripheral organization of the chromatophore system of Eledone cirrhosa at the level of the chromatic and physiological units.The structure of the chromatic elements is investigatedwith light and electron-microscopy. The structure of the leucophores and iridophores of E. cirrhosa is similar to thestatic elements of other octcpods. The leucophores consistof a central cell body bearing ovoid electron-dense protrusions (leucosomes). The iridophores are made of a central cell body surrounded by stacks of electron-dense discoidal platelets(iridosomes). The chromatophores are true organs made of a central cell containing the pigment granules, surrounded by fifteen to twenty radially arranged muscle fibers. The contraction of the muscles produces expansion of the pigmentcell. The radial muscles are of the obliquely striated type. They differ from those of squids in that the contractile filaments occupy the core of the fiber and they contain fewer mitochondriae. Most of the chromatophore muscles are innervated in an "en passant" fashion by thin varicose axons whichcontact some of the muscles of several chromatophores. The f chromatic units represent morphological groupings of the three elements.The innervation of the chromatophore muscles investigated with cobalt filling or stimulation of nerve bundles in the skin with suction electrodes. The chromatophores forming a motor unit are dispersed over several chromatic units and probablyrepresent parts of particular patterns. There is evidence that variations of the stimulus frequency modifies the numberof chromatophores triggered by a single axon. It is thus suggested that recruitment of motor units is responsible for the different patterns seen in vivo while recruitment through frequency could account for the intensity with which these patterns are expressed.
6

Functional morphology of cephalopod gills /

Eno, N. Clare. January 1987 (has links)
Thesis (Ph. D.)--University of Cambridge, 1987. / Typescript.
7

Mechanisms of Coexistence Between Two Octopus Species In A South Florida Lagoon

Unknown Date (has links)
Theoretically, sympatric species must partition resources or space to allow for coexistence. Determining empirically the specific resources each species exploits and species’ interactions (e.g., intra- and interspecific competition) can sometimes be challenging, thus the data are relatively sparse for certain taxa. This paucity of data exists for octopuses. Therefore, I chose to study niches of two sympatric octopuses (Octopus vulgaris and Macrotritopus defilippi) in an intracoastal habitat. Specifically, I assessed (1) spatial distribution of octopus home or “den” space, (2) habitat association, (3) octopus abundance, (4) foraging activity periods, (5) diet, and (6) associated substrates and behaviors used during foraging events. Octopus den locations were marked by GPS to quantify spatial patterns of both species and their spatial relationship to each other. Habitat associations were measured by quantifying photoquadrats of den and surrounding habitats. For foraging activity periods, a video camera was placed near an octopus den for 24-h observation to determine when each octopus species leaves/returns from foraging. Underwater video recording was used to determine associated foraging substrates and behaviors for both species. Prey remains from octopus’ dens and video recordings indicating prey consumption were used to determine diets of the two octopus species. Video recordings from the 24-h camera and foraging behavior events also provided observations of intra- and interspecific interactions. Results revealed that the two species are interspersed throughout the shallow Florida lagoon and are both abundant during the spring months (March, April, May). Although both species are interspersed throughout the lagoon, their den and surrounding habitat association differed. O. vulgaris was associated with hard bottom and M. defilippi was associated with soft bottom, thus they may not compete strongly for habitats. Each species used different foraging strategies and different primary prey, which may also lessen competition and facilitate coexistence. O. vulgaris had peak foraging activity during night hours, foraged mostly on hard bottom and mainly consumed bivalves while M. defilippi had peak foraging activity during day hours, foraged mostly on soft bottom and mainly consumed crustaceans. Octopuses also had species-specific foraging behaviors, with O. vulgaris using parachute attack and M. defilippi using flounder swimming and tripod stance. Additional intra- and interspecific interactions were video recorded and included: fishes following octopuses, predation attempts, agonistic encounters, cannibalism, and tactile communication. This study identified ecological and behavioral components that may facilitate coexistence of these sympatric species, provided insight into cephalopod niches and ecology, and provided baseline conservation requirements for sand-dwelling cephalopods, both of which may be using this site as a mating and nursery habitat. / Includes bibliography. / Dissertation (Ph.D.)--Florida Atlantic University, 2019. / FAU Electronic Theses and Dissertations Collection
8

Some aspects of the anatomy of the alimentary canal of the lesser octopus, Eledone cirrhosa (Lamarck 1817), with special reference to the nervous system

Polglase, Jane L. January 1980 (has links)
The modern cephalopod molluscs, particularly the octopods, are highly developed macrophageous predators which have a pronounced ability to learn. Striking resemblances are found between these animals and the vertebrates, particularly the fish. The study of cephalopods therefore provides an opportunity to examine systems which are composed of structural units common to molluscs but which may be similar in function and performance to those of vertebrates. This investigation concerns the alimentary canal and its innervation in the lesser octopus Eledone cirrhosa. Detailed anatomical investigation shows the alimentary canal of E. cirrhosa to be very similar to that of the better known Octopus vulgaris. Current concepts of the functions of the alimentary organs are discussed utilizing data from both E. cirrhosa and O. vulgaris. Silver staining reveals a basic pattern of innervation in the alimentary organs. Large nerve trunks running in the external collagenous layer give rise to a nerve plexus within the circular muscle. The longitudinal muscle plexus arises from branches of the circular muscle plexus or direct from the nerves of the external layer, Nerves of both plexuses contact muscle fibres in an 'en passant' manner. Fibres run out from the longitudinal muscle to the subepithelium, where they are observed associated with muscle fibres and beneath the epithelial basal lamina. Good evidence for fibres crossing into the epithelium was observed only in the cuticularized regions of the digestive tract. The digestive gland ducts differ from this pattern in the very large numbers of major nerves seen in their external and muscular regions. Outwith the alimentary ganglia nerve cells are only regularly observed within the major intestinal nerves. Receptor like cells were also repeatedly observed only in the posterior intestine. These results axe compared with data from O. vulgaris and the physiological evidence for the presence of receptors. The blood vessels of the alimentary canal are innervated at all levels. The distribution of other densely staining cells is reported. Evidence for the presence of particular neurotransmitters within the alimentary canal and alimentary nerve centres is reviewed. Fluorescence histochemistry shows that at least two types of nerves are present in the alimentary wall. The majority axe aminergic (including those associated with blood vessels and some sphincters), as the pattern of fluorescent nerves is predominantly that shown by silver studies. However, fluorescent nerves decrease and then disappear anteriorly from the crop/oesophageal sphincter and posteriorly from the mid-intestine. The stomach has fluorescent nerves, other than those associated with blood vessels. Fluorescent fibres enter the gut via the sympathetic and possibly the digestive gland duct nerves. Non-fluorescent fibres enter via the atrio-rectal nerves and from the gastric ganglion. The fluorescence is ascribed to catecholamines as no evidence of 5HT was obtained, Specific fluorescence was also observed in some cells of the subepithelium and the external region. These results are discussed with reference to available physiological data. The anterior intestine was the representative region chosen for fine structural studies. These show the alimentary muscles to be the same basic type (cross or pseudo-striated) as that found in cephalopod somatic or heart muscle. Three types of myomuscular and neuromuscular junctions axe described. The presence of mineralized concretions (spherites) in the external layer of the intestine, together with the complex relations of its epithelial cells and heavy vascularization suggest a secondary function of mineral and/or water balance for this organ. These results are discussed. Finally, a pathological condition affecting the octopuses during this study is described.

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