DOCSLIB.ORG

(MOLLUSCA, NUDIBRANCHIA). by A. M. Ayling*

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
(MOLLUSCA, NUDIBRANCHIA). by A. M. Ayling* Tane (1968) lh: 25-k2 25 THE FEEDING BEHAVIOUR OF ROSTANGA RUBICUNDA (MOLLUSCA, NUDIBRANCHIA). By A. M. Ayling* INTRODUCTION Most members of the order Nudibranchia are spec• ialised carnivores feeding on sessile and encrusting animals such as hydroids, polyzoans, Porifera, ascldians and alcyonarians. All have different means of feeding eg. scraping, tearing or sucking and differ• ent modifications especially in the buccal mass. The least specialised of these grazing carnivores are the members of the Doridacea which feed on sponges. Most are brightly coloured either for camouflage when on the food sponge or to serve as a warning for predat• ors. The bright red Rostanga rufescens of Britain feeds on the encrusting red sponge Microciona in the order Poecilosclerida (Morton) and the very similar R. pulchra (MacFarland) of North America feeds on a sponge of the same order Ophlitaspongia penata (Cook 1962). The New Zealand species R. rubicunda (Cheeseman) occurs commonly on Westmere reef, Auckland, in association with three very similar sponges. Microciona coccinea Holoplocamium neozelanicum Ophlitaspongia seriata The feeding of R. rubicunda in relation to these three sponges was investigated using a number of techniques. The food of carnivores and scavengers is frequ• ently local and specific and thus chemoreception from a distance is undoubtedly important in feeding behav• iour. R. pulchra is attracted to Ophlitaspongia pennata by chemotaxis (Cook 1962) and it was thought that the same was probably true of the relationship between R. rubicunda and one or more of the above ^Department of Zoology, University of Auckland. 26 mentioned sponges. The small size of this dorid and its ease of collection make it possible to attempt the type of feeding behaviour experiments used by Stehouwer (1952), Braams and Geelen (1953) and Cook (1962) to determine its food preferences and other aspects of its feeding behaviour. This method was substantiated by making spicule mounts of gut contents and faeces to determine the sponges eaten and also by observing the animal in the field. FIG. 1. ROSTANGA RUBICUNDA. EXTERNAL CHARACTERS Rostanga rubicunda (Cheeseman l88l) is a small bright scarlet nudibranch that seems to be very close to the British R. rufescens and the North American R. pulchra, MacFarland. The mantle is covered with minute, closely packed, erect tubercules and the foot 27 extends a short distance posteriorly to this. The rhinophores are completely retractable and have 12 broad laminae which run obliquely upwards. The apex is a small projecting flat topped style. The rhino• phores of nudibranchs were developed following the loss of ctenidia and the osphradium as a replacement sensory area and are clubbed and finely plicate to increase the sensory epithelium. They contain relat• ively large lobed ganglia associated with the recep• tors. In Rostanga the rhinophores seem to be used for detecting the presence of the food sponge at a distance ie. by chemotaxis (Cook 1962) although Augersberg (1922) after experiments with food extrac• ts concluded that the rhinophores were not involved with chemoreception at a distance. However, placed as they are in an anterior, elevated position it would be fair to suggest that the function of the rhinophores is similar to that of the osphradium they replace ie. to test the water flowing over them for contained chemicals, either favourable (food) or un• favourable. The gills (branchiae) are also retract• able, eight in number, erect and bipinnate. ECOLOGY Rostanga rubicunda can be found occasionally in the sublittoral fringe on most protected rocky shores in the North Auckland area, eg. Eastern beach, Waiwera, Takapuna, Bonaccord harbour, Leigh. It is, however, limited in numbers in most of these areas by the scarcity of its food. But on Westmere reef which straddles the main tidal stream of Auckland Harbour the detritus rich waters which surge twice daily across it provide ample nourishment for a prolific growth of sponges. The three food sponges of Rostan• ga rubicunda occur quite commonly amongst these and this slug occurs in considerable numbers at this lo• cality. In this area the slugs are not found as part of the under-stone fauna but prefer more open situa• tions even though their food sponges are often pres• ent under stones. Approximately 50% of the Rostanga population were found feeding on the red food sponges. The sponges eaten by 20 of these feeding slugs were 28 identified using spicule mounts. II were feeding on Ophlitaspongia 7 " " " Microciona 2 " " " Holoplocamium Rostanga was found in considerable numbers over the entire period during which they were examined, ie. from early March to September. Powell (1957) states that it also occurs commonly over the months September to November. Thus it is probable that this animal may be found throughout the year with equal abundance. The smallest slugs collected were about 10 mms. in length and the largest 33 mms. with an average of 15-20 mms. FEEDING BEHAVIOUR Materials and Methods Rostanga rubicunda3 as has been pointed out, is always found where its food sponges are present and as sponges occur in regions where there is consider• able water movement it should be possible for the animal to trace its food by detecting secretions from the sponge and following them through the current to their source, ie. by chemotaxis. As Rostanga feeds on at least three sponges the response to each sponge would be expected to increase with the slugs' prefer• ence for that sponge as food. To test this an arti• ficial current flow was set up in the laboratory and arranged so that the slugs could be given a choice between two sponges. To achieve this seawater was run into two bowls in which the various sponges could be placed and then siphoned out into a single shallow tray in which the slugs to be tested were placed. The water was allowed to overflow from the tray and run to waste as it could not be recirculated without mixing the sponge "odours". The apparatus use is shown in Fig. 6, and diagramatically in Fig. 2. (i) Using this apparatus five fairly similar sponges from Westmere were tested against blank controls and against each other to find out which were eaten by Rostanga and the order of preference 29 MCOMINO 5CAWATER SLUG TRAY 'lilt OVF»FLOW * INFLOW FIG. 2. CURRENT FLOW APPARATUS. amongst these. These sponges were: - Ophlitaspongia seriata Holoplocamium neozelanicum Microciona coccinea Hymeniacidon perleve Suberites cupuloides Other aspects of Rostanga's feeding behaviour were tested using this apparatus, viz. (ii) Gregariousness - a few of the slugs themselves were placed in one of the sponge howls to see the slugs in the tray were affected at all. 30 (iii) The "fouling" effects of other encrusting org• anisms and algae found associated with the sponges on the reaction of the slugs was inves• tigated to see if the presence of secretions from other organisms masked those from the sponge and confused the slugs' sensory mechan• isms. (iv) The effects of varying the current speed were tested by regulating the siphoning height be• tween the bowls and the tray. (v) The effects of light or dark On the slugs' reactions were tested to see if feeding activ• ity was greater during the day than at night or vice versa. (vi) The minimum amount of sponge needed to give a definite reaction was investigated. To see if the slugs could detect the sponges without water movement another apparatus was set up in which the sponge secretions could only reach the slugs by diffusion. In this the two sponge bowls were placed at either end of the tray containing the slugs; the three linked by water bridges. These bridges were made as short as possible to minimise the diffusion path (see Fig. 3. ). After five 3 hr. experiments using sponges that evoked a considerable reaction in the current flow apparatus and 35 speci• mens of Rostanga in the tray none of the animals had responded. It is thus probable that water movement is necessary to enable Rostanga to detect and seek out its food. Results Each experiment was run for three hours and at the end of that time the animals in each sponge bowl were counted. The number of animals remaining in each tube was also noted and both figures recorded as percentages. The slugs were removed from the bowls as soon as they reached them to prevent feeding on the sponges. 31 SIPHON *—z^T^ SPONGE SPONGE BOWL •OWL FIG. 3. DIFFUSION APPARATUS Table 1. Controls Run no. Bowl Contents of bowl % in bowl %in tube I. A. nil 2. 7 0 B nil 1. 1+ 0 2 A nil 0 0 B nil 0 0 Feeding preference experiments 3 A nil 0 1. 1+ B l+. 55gm. Ophlitaspongia 26 13. 7 1+ A l+. 55gm. Ophlitaspongia 31. 5 5-5 B nil 0 0 5 A 2. 25gm. Ophlitaspongia 20. 6 l+. l B 2. 3gm. Ophlitaspongia 15-1 9. 6 6 A nil 1. 1+ 1. 1+ B lgm. Holoplocamium 6. 9 7 A 3-71gm. Holoplocamium 2. fk 6. 9 B nil 0 1. 1+ Feeding preference experiments. Gregariousness "Fouling" effects 33 (Table 1. continued) Run no. Bowl Contents of bowl % in bowl % in tube "Fouling" effects 22 b Microciona 23. 3 10 Variation of current speed 23 A Microciona with current 0 0 velocity of 0. 86 m. p. h. B Microciona with current 26 10 velocity of O. 58 m. p. h. 2k A Microciona with current 3 5 velocity of 0. 75 m. p. h. B Microciona with current 25 8 velocity of 0. 58 m. p. h. 25 A Microciona with current 27 3 velocity of 0. 7 m. p. h. B Microciona with current 7 1 velocity of O.
Load more

Recommended publications
  • Comparative Neuroanatomy of Mollusks and Nemerteans in the Context of Deep Metazoan Phylogeny
    Comparative Neuroanatomy of Mollusks and Nemerteans in the Context of Deep Metazoan Phylogeny Von der Fakultät für Mathematik, Informatik und Naturwissenschaften der RWTH Aachen University zur Erlangung des akademischen Grades einer Doktorin der Naturwissenschaften genehmigte Dissertation vorgelegt von Diplom-Biologin Simone Faller aus Frankfurt am Main Berichter: Privatdozent Dr. Rudolf Loesel Universitätsprofessor Dr. Peter Bräunig Tag der mündlichen Prüfung: 09. März 2012 Diese Dissertation ist auf den Internetseiten der Hochschulbibliothek online verfügbar. Contents 1 General Introduction 1 Deep Metazoan Phylogeny 1 Neurophylogeny 2 Mollusca 5 Nemertea 6 Aim of the thesis 7 2 Neuroanatomy of Minor Mollusca 9 Introduction 9 Material and Methods 10 Results 12 Caudofoveata 12 Scutopus ventrolineatus 12 Falcidens crossotus 16 Solenogastres 16 Dorymenia sarsii 16 Polyplacophora 20 Lepidochitona cinerea 20 Acanthochitona crinita 20 Scaphopoda 22 Antalis entalis 22 Entalina quinquangularis 24 Discussion 25 Structure of the brain and nerve cords 25 Caudofoveata 25 Solenogastres 26 Polyplacophora 27 Scaphopoda 27 i CONTENTS Evolutionary considerations 28 Relationship among non-conchiferan molluscan taxa 28 Position of the Scaphopoda within Conchifera 29 Position of Mollusca within Protostomia 30 3 Neuroanatomy of Nemertea 33 Introduction 33 Material and Methods 34 Results 35 Brain 35 Cerebral organ 38 Nerve cords and peripheral nervous system 38 Discussion 38 Peripheral nervous system 40 Central nervous system 40 In search for the urbilaterian brain 42 4 General Discussion 45 Evolution of higher brain centers 46 Neuroanatomical glossary and data matrix – Essential steps toward a cladistic analysis of neuroanatomical data 49 5 Summary 53 6 Zusammenfassung 57 7 References 61 Danksagung 75 Lebenslauf 79 ii iii 1 General Introduction Deep Metazoan Phylogeny The concept of phylogeny follows directly from the theory of evolution as published by Charles Darwin in The origin of species (1859).
    [Show full text]
  • A Phylum-Wide Survey Reveals Multiple Independent Gains of Head Regeneration Ability in Nemertea
    bioRxiv preprint doi: https://doi.org/10.1101/439497; this version posted October 11, 2018. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY-NC 4.0 International license. A phylum-wide survey reveals multiple independent gains of head regeneration ability in Nemertea Eduardo E. Zattara1,2,5, Fernando A. Fernández-Álvarez3, Terra C. Hiebert4, Alexandra E. Bely2 and Jon L. Norenburg1 1 Department of Invertebrate Zoology, National Museum of Natural History, Smithsonian Institution, Washington, DC, USA 2 Department of Biology, University of Maryland, College Park, MD, USA 3 Institut de Ciències del Mar, Consejo Superior de Investigaciones Científicas, Barcelona, Spain 4 Institute of Ecology and Evolution, University of Oregon, Eugene, OR, USA 5 INIBIOMA, Consejo Nacional de Investigaciones Científicas y Tecnológicas, Bariloche, RN, Argentina Corresponding author: E.E. Zattara, [email protected] Abstract Animals vary widely in their ability to regenerate, suggesting that regenerative abilities have a rich evolutionary history. However, our understanding of this history remains limited because regeneration ability has only been evaluated in a tiny fraction of species. Available comparative regeneration studies have identified losses of regenerative ability, yet clear documentation of gains is lacking. We surveyed regenerative ability in 34 species spanning the phylum Nemertea, assessing the ability to regenerate heads and tails either through our own experiments or from literature reports. Our sampling included representatives of the 10 most diverse families and all three orders comprising this phylum.
    [Show full text]
  • Mollusca Three Classes
    Mollusca Three Classes 1. Gastropoda (gastropods)~ slugs and snails 2. Bivalvia (bivalves) ~ clams and other two- shelled shellfish 3. Cephalopoda (cephalopods) ~ squids, octopuses and cuttlefish 1 Bodies of Mollusks • A mollusk has a soft body which is usually covered by a hard outer shell. • Exceptions: – Slugs and octopuses have lost their shells through evolution – Squids have very reduced shells Anatomy of a Mollusk • All mollusks have: – Foot ~ the muscular foot helps it move – Visceral mass ~ contains the gills, gut, and other organs – Mantle ~ covers the visceral mass to protect the mollusks without shells • Most mollusks have: – Shell ~ protects the mollusk from predators and keeps land mollusks from drying out. 2 Symmetry of Mollusks • Mollusks have bilateral symmetry. – The two halves of the body mirror each other. Anatomy of a Snail (gastropod) 3 Anatomy of a Clam (bivalve) Anatomy of a Squid (cephalopod) 4 Eating Behaviors • Bivalves (clams) ~ filter tiny plant and bacteria from the water • Gastropods (snails) ~ eat with a radula (tiny tongue covered with teeth. – The radula is used to scrape algae off rocks and pieces of leaves and seaweed • Cephalopods (squid) ~use tentacles to grab their prey and put it in their powerful jaws. Blue-ringed octopus 5 Market Squid Moon Snail chasing its food 6 Achatina fulica Giant African Land Snail The largest land snail known is the Giant African Land Snail. It can weigh up to 2 pounds and be 15 inches long. Commonly Eaten Mollusks cockles conch oysters clams scallops abalone whelks Mussels Pen shells 7.
    [Show full text]
  • Chemoreception in Spider Conch, Lambis Lambis (Mollusca: Gastropoda)
    Sm all er Re s e ar ch Cont r ib utions 111 Chemoreception in spider conch, Lambis lambis (Mollusca: Gastropoda) V. Deepak Samuel & |amila Patterson Samuel, V.D. & J. Patterson. 2001. Chemoreception in spider conch, Lambis lambis (Mollusca: Gastropoda) - Phuket Marine Biological Center Special Publication 25(1,): 111,-11,2. Extracts of sea weed, clam, fish, crab, acid, base and commercial agar were used in chemoreception tests of Lambislambis. This species exhibited a faster response towards extracts of red algae (Hypnea muscifurmis, Hypenea aalentise and Gracilnria corticatn) than towards other extracts. V. Deepak Samuel and I amila P ntterson. Suganthi Deuadason Marine Research lnstitute 44, Beach Road, Tuticorin - 528 001,India. E-mail : s dmar i@m d4.u snl. ne t. in the laboratory. They were starved for 7 days INTRODUCTION before the olfactory tests. A11 the animals Gastropods possess a sensory organ referred measured about 13.5 cm in length. Tests were to as the osphradium. It consists of patches of performed in rectangular tanks containing epithelium located on the posterior margin of filtered sea water. each afferent gill membrane and they function Extracts were made of plants and animals: as chemoreceptors. The osphradium can also red algae Graciloria corticata, Hypnea detect the amount of sediment in the inhalant musciformls and H. aalentine, greer. algae Ulaa current (Barnes 1987). The gastropods receive lactuca, brown algae Sargassum ruightii, the stimuli through the respiratory current. The clams Meretrix meretrix and Donax cuneAtus, time needed for olfactory detection may vary cuttlefish Sepiabreaimana, crab Cancer Sp., and between species. fish Sillago sihama were selected and about 50 Four types of reaction to stimuli have been g were homogenized (1:1; v l*).
    [Show full text]
  • GY 112L: Earth History Lab
    UNIVERSITY OF SOUTH ALABAMA GY 112L: Earth History Lab Week 9: Paleozoic Part 3 Instructor: Dr. Douglas W. Haywick Today’s Agenda The Paleozoic Part 3 (Week 9 exercises) 1) Brachiopods 2) Molluscs 3) Alabama Stratigraphy Brachiopoda Brachiopod Facts: Taxonomy: (under review) Phylum: Brachiopoda Class: Inarticulata Class: Articulata Brachiopoda Brachiopod Facts: Taxonomy: Phylum: Brachiopoda Class: Inarticulata Class: Articulata Range: Cambrian-Recent (Inarticulates were first) Brachiopoda Brachiopod Facts: Taxonomy: Phylum: Brachiopoda Class: Inarticulata Class: Articulata Range: Cambrian-Recent Mode of Life: Marine, benthic, filter feeder Brachiopoda Brachiopod Facts: Taxonomy: Phylum: Brachiopoda Class: Inarticulata Class: Articulata Range: Cambrian-Recent Mode of Life: Marine, benthic, filter feeder Mineral composition: calcite, phosphate Brachiopoda Brachiopod Facts: Taxonomy: Phylum: Brachiopoda Class: Inarticulata Class: Articulata Range: Cambrian-Recent Mode of Life: Marine, benthic, filter feeder Mineral composition: calcite, phosphate Fossil Pres.: pristine (sometimes external molds) The Brachiopod Animal Inarticulates The Brachiopod Animal Inarticulates Brachiopod Symmetry Symmetrical across the valves (down the medial line) Brachiopod Symmetry Symmetrical across the valves (down the medial line) Brachiopod Symmetry Symmetrical across the valves (down the medial line) Articulate Brachiopods Brachiopod Symmetry Symmetrical across the valves (down the medial line) Articulate Brachiopods Brachiopod Symmetry Not symmetrical between
    [Show full text]
  • Tropical Marine Invertebrates CAS BI 569 Phylum ANNELIDA by J
    Tropical Marine Invertebrates CAS BI 569 Phylum ANNELIDA by J. R. Finnerty Phylum ANNELIDA Porifera Ctenophora Cnidaria Deuterostomia Ecdysozoa Lophotrochozoa Chordata Arthropoda Annelida Hemichordata Onychophora Mollusca Echinodermata Nematoda Platyhelminthes Acoelomorpha Silicispongiae Calcispongia PROTOSTOMIA “BILATERIA” (=TRIPLOBLASTICA) Bilateral symmetry (?) Mesoderm (triploblasty) Phylum ANNELIDA Porifera Ctenophora Cnidaria Deuterostomia Ecdysozoa Lophotrochozoa Chordata Arthropoda Annelida Hemichordata Onychophora Mollusca Echinodermata Nematoda Platyhelminthes Acoelomorpha Silicispongiae Calcispongia PROTOSTOMIA “COELOMATA” True coelom Coelomata gut cavity endoderm mesoderm coelom ectoderm [note: dorso-ventral inversion] Phylum ANNELIDA Porifera Ctenophora Cnidaria Deuterostomia Ecdysozoa Lophotrochozoa Chordata Arthropoda Annelida Hemichordata Onychophora Mollusca Echinodermata Nematoda Platyhelminthes Acoelomorpha Silicispongiae Calcispongia PROTOSTOMIA PROTOSTOMIA “first mouth” blastopore contributes to mouth ventral nerve cord The Blastopore ! Forms during gastrulation ectoderm blastocoel blastocoel endoderm gut blastoderm BLASTULA blastopore The Gut “internal, epithelium-lined cavity for the digestion and absorption of food sponges lack a gut simplest gut = blind sac (Cnidaria) blastopore gives rise to dual- function mouth/anus through-guts evolve later Protostome = blastopore contributes to the mouth Deuterostome = blastopore becomes the anus; mouth is a second opening Protostomy blastopore mouth anus Deuterostomy blastopore
    [Show full text]
  • Lab 5: Phylum Mollusca
    Biology 18 Spring, 2008 Lab 5: Phylum Mollusca Objectives: Understand the taxonomic relationships and major features of mollusks Learn the external and internal anatomy of the clam and squid Understand the major advantages and limitations of the exoskeletons of mollusks in relation to the hydrostatic skeletons of worms and the endoskeletons of vertebrates, which you will examine later in the semester Textbook Reading: pp. 700-702, 1016, 1020 & 1021 (Figure 47.22), 943-944, 978-979, 1046 Introduction The phylum Mollusca consists of over 100,000 marine, freshwater, and terrestrial species. Most are familiar to you as food sources: oysters, clams, scallops, and yes, snails, squid and octopods. Some also serve as intermediate hosts for parasitic trematodes, and others (e.g., snails) can be major agricultural pests. Mollusks have many features in common with annelids and arthropods, such as bilateral symmetry, triploblasty, ventral nerve cords, and a coelom. Unlike annelids, mollusks (with one major exception) do not possess a closed circulatory system, but rather have an open circulatory system consisting of a heart and a few vessels that pump blood into coelomic cavities and sinuses (collectively termed the hemocoel). Other distinguishing features of mollusks are: z A large, muscular foot variously modified for locomotion, digging, attachment, and prey capture. z A mantle, a highly modified epidermis that covers and protects the soft body. In most species, the mantle also secretes a shell of calcium carbonate. z A visceral mass housing the internal organs. z A mantle cavity, the space between the mantle and viscera. Gills, when present, are suspended within this cavity.
    [Show full text]
  • Phylum Mollusca: Macroevolution Module Instructor’S Guide Lesson by Kevin Goff
    Phylum Mollusca: Macroevolution Module Instructor’s Guide Lesson by Kevin Goff Overview: Through a sequence of engaging laboratory investigations coupled with vivid segments from the acclaimed Shape of Life video series, students explore the fascinating structural and behavioral adaptations of modern molluscs. But rather than study these animals merely as interesting in the here-and-now, students learn to view them as products of a 550 million year evolution. Students interpret their diverse adaptations as solutions to the challenges of life in a dangerous world. They use the Phylum Mollusca to undersand three major macroevolutionary patterns: divergent evolution, convergent evolution and coevolution. Grades: 7-12. There are high and middle school versions of each lab activity. Subjects: Biology, earth science, ecology, paleontology, evolutionary science Standards: See at the end of this document. Instructional Approach: In general, these lessons use an “explore-before-explain” pedagogy, in which students make and interpret observations for themselves as a prelude to formal explanations and the cultivation of key scientific concepts. There are exercises in inquiry and the scientific process using authentic data, where students are pressed to think at higher cognitive levels. Instruction is organized around three unifying themes – the macroevolutionary patterns of divergence, convergence, and coevolution – and students learn to interpret diverse biological examples of these patterns. Suggested Lesson Sequence: This module comprises four lessons. Each is written so that it can be used either as a stand-alone lesson, or as a piece in a longer unit. Logistics and other details for each lesson are provided in separate instructor’s guides. To do the full unit, follow this sequence: 1.
    [Show full text]
  • Beachcombers Field Guide
    Beachcombers Field Guide The Beachcombers Field Guide has been made possible through funding from Coastwest and the Western Australian Planning Commission, and the Department of Fisheries, Government of Western Australia. The project would not have been possible without our community partners – Friends of Marmion Marine Park and Padbury Senior High School. Special thanks to Sue Morrison, Jane Fromont, Andrew Hosie and Shirley Slack- Smith from the Western Australian Museum and John Huisman for editing the fi eld guide. FRIENDS OF Acknowledgements The Beachcombers Field Guide is an easy to use identifi cation tool that describes some of the more common items you may fi nd while beachcombing. For easy reference, items are split into four simple groups: • Chordates (mainly vertebrates – animals with a backbone); • Invertebrates (animals without a backbone); • Seagrasses and algae; and • Unusual fi nds! Chordates and invertebrates are then split into their relevant phylum and class. PhylaPerth include:Beachcomber Field Guide • Chordata (e.g. fi sh) • Porifera (sponges) • Bryozoa (e.g. lace corals) • Mollusca (e.g. snails) • Cnidaria (e.g. sea jellies) • Arthropoda (e.g. crabs) • Annelida (e.g. tube worms) • Echinodermata (e.g. sea stars) Beachcombing Basics • Wear sun protective clothing, including a hat and sunscreen. • Take a bottle of water – it can get hot out in the sun! • Take a hand lens or magnifying glass for closer inspection. • Be careful when picking items up – you never know what could be hiding inside, or what might sting you! • Help the environment and take any rubbish safely home with you – recycle or place it in the bin. Perth• Take Beachcomber your camera Fieldto help Guide you to capture memories of your fi nds.
    [Show full text]
  • Marine Flora and Fauna of the Northeastern United States Erect Bryozoa
    NOAA Technical Report NMFS 99 February 1991 Marine Flora and Fauna of the Northeastern United States Erect Bryozoa John S. Ryland Peter J. Hayward U.S. Department of Commerce NOAA Technical Report NMFS _ The major responsibilities of the National Marine Fisheries Service (NMFS) are to monitor and assess the abundance and geographic distribution of fishery resources, to understand and predict fluctuations in the quantity and distribution of these resources, and to establish levels for their optimum use. NMFS i also charged with the development and implementation of policies for managing national fishing grounds, development and enforcement of domestic fisheries regulations, urveillance of foreign fishing off nited States coastal waters, and the development and enforcement of international fishery agreements and policies. NMFS also assists the fishing industry through marketing service and economic analysis programs, and mortgage in­ surance and ve sel construction subsidies. It collects, analyzes, and publishes statistics on various phases of the industry. The NOAA Technical Report NMFS series was established in 1983 to replace two subcategories of the Technical Reports series: "Special Scientific Report-Fisheries" and "Circular." The series contains the following types of reports: Scientific investigations that document long-term continuing programs of NMFS; intensive scientific report on studies of restricted scope; papers on applied fishery problems; technical reports of general interest intended to aid conservation and management; reports that review in considerable detail and at a high technical level certain broad areas of research; and technical papers originating in economics studies and from management investigations. Since this is a formal series, all submitted papers receive peer review and those accepted receive professional editing before publication.
    [Show full text]
  • Mollusks Phylum Mollusca
    Mollusks Phylum Mollusca There are more than 50,000 species in this phylum. Mollusks are invertebrates and include octopus, squid, snails, slugs, clams, and oysters and many others. As diverse as this phylum is, all its animals include three physical traits. They have whatis refered to as the visceral mass, mantle and foot. The visceral mass includes body organs – the digestive tract, renal and reproductive organs. The mantle partially covers the visceral mass and may secrete a shell in some mollusks. The foot is a muscular structure that has many functions in different mollusks including movement, attachment, and predation. Many mollusks also contain a radula with many rows of sharp teeth for scraping at food sources. Habitat: They are found in both salt (marine) and freshwater habitats and on land. Class Gastropoda The gastropods include snails, slugs, conchs, periwinkles and sea slugs. Habitat: They are found in both salt (marine) and freshwater habitats and on land. Diet: Some gastropods are herbivores using the radula to scrape off food particles. Others are carnivores and use the radula to penetrate the shells of their prey. Physical Traits: They have a large, muscular foot on which they move slowly along any surface and the visceral mass sits atop the foot. Many gas- tropodes have shells, though not all. Both the slug and the sea slug (nudibranch) lack a shell. Snails and slugs breathe through respiratory pores, the oxygen being absorbed directly into the abundant tiny blood vessels of the mantle. In the more aquatic gastropods, there are gills instead. Snails have an odd development, the young going through a torsion that results in the anus emptying wasteout at the back of the head.
    [Show full text]
  • Velum (Bivalvia: Mollusca) (Chemoautotroph/Sulfur-Oxidizing Bacteria/Deep-Sea Hydrothermal Vents/Symbiosis) COLLEEN M
    Proc. Nati. Acad. Sci. USA Vol. 85, pp. 7786-7789, October 1988 Microbiology Immunochemical localization of ribulose-1,5-bisphosphate carboxylase in the symbiont-containing gills of Solemya velum (Bivalvia: Mollusca) (chemoautotroph/sulfur-oxidizing bacteria/deep-sea hydrothermal vents/symbiosis) COLLEEN M. CAVANAUGH*, MARILYN S. ABBOTT*t, AND MARTEN VEENHUISt *Harvard University, The Biological Laboratories, 16 Divinity Avenue, Cambridge, MA 02138; tAnheuser-Busch Companies, Corporate Research and Development, Saint Louis, MO 63118; and *Laboratory of Electron Microscopy, University of Groningen, Biological Centre, Kerklaan 30, 9751 NN Haren, The Netherlands Communicated by Lawrence Bogorad, June 9, 1988 (receivedfor review March IS, 1988) ABSTRACT The distribution of the Calvin cycle enzyme set out to localize this enzyme in the clam tissue by immu- ribulose-1,5-bisphosphate carboxylase (RbuP2Case; EC 4.1.1.39) nochemical means. was examined by using two lmmunologkal methods in tissues of The RbuP2Case holoenzyme of vascular plants, green Solentya velum, an Atlantic coast bivalve containing putative algae, and most bacteria is a high molecular mass complex chemoautotrophic symbionts. Antibodies elicited by the purified (-550 kDa) composed of eight large subunits and eight small large subunit of RbuP2Case from tobacco (Nicotana tabacum) subunits, with molecular masses of 50-56 kDa and 11-15 cross-reacted on immunoblots with a protein ofsimilar molecular kDa, respectively (3, 4). The enzyme catalyzes both car- mass occurring in extracts ofthe symbiont-containing gill tissue of boxylation and oxygenation reactions by using ribulose S. velum. No cross-reactivity was detected in symbiont-free tissue 1,5-bisphosphate as a substrate. Although the function ofthe extracts.
    [Show full text]