Invertebrates

The Evolutionary History of Nematodes (Nematology Monographs

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Skin-digging tanaids: the unusual parasitic behavior of Exspina typica Lang, 1968 in Antarctic waters and worldwide deep basins. I was recently asked to provide some more information about medusa worms in one of the forums, and while searching the web to provide some links, I realized that there is very little information out there about the biology and aquarium care of these fascinating animals. Der DNA-Gehalt der Zellen bei dem primitiven Metazoon Trichoplax adhaerens F. It has become apparent that certain harpacticoid copepods are strongly associated with some of these bluegreens.

Advances in Trematode Biology

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All of these kinds of “char- acters” have been used to create phylogenetic trees. Subclass Pentastomida Obligatory parasites of reptiles, mammals, and birds. It is important for everyone, especially the science and zoology students, to differentiate between vertebrates and invertebrates. The vol- ume of gonadal tissue varies seasonally, and during the reproductive period it may occupy so much of the body as to interfere with feeding. The larva eventually settles on its aboral end and tenta- cles grow around the upwardly directed mouth and oral disc.

Reptiles in Research: Investigations of Ecology, Physiology,

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Academic Press, New York. [A scholarly series of state-of-the-art reviews on various aspects of protist physiology and chemistry.] Levine, N. A transla- tion of the original German paper that introduced the colonial the- ory of metazoan origin (Jena. In contrast to this fully indirect life-history pattern, many compound as- cidians composed of tiny zooids produce relatively few eggs, but each egg has a high yolk content. Catalogue of American Amphibians and Reptiles. (Published by the American Society of Ichthyologists and Herpetologists, 1963-1970.) Stebbins, R.

Arthropod Relationships (The Systematics Association Special

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This is the simplest kind of cellular organization found among parazoans. Many of these animals also feed on detritus by simply picking up particles with their chelipeds. Vermi- form, with three body regions as proboscis, collar and trunk; coeloms reduced; gut elongate, straight; mouth ventral at an- terior end of collar; without an endostyle; anus posterior, ter- minal; marine, burrow in soft sediments or nestle under rocks or in algal holdfasts; largely intertidal although a few deep- water species are known.

Stem Cells in Marine Organisms

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Although virtually nothing is known about excre- tory physiology in phoronids, particulate crystalline matter has been observed exiting the nephridiopores and probably represents precipitated nitrogenous waste products. Rhabdopleura bears one pair of arms, each with numer- ous tentacles, whereas Cephalodiscus bears from five to nine pairs of arms, depending on the species. In these cases, chlorophyll may no longer be present (although the carotenoid pig- ments usually remain) and the organisms have switched to heterotrophy, often relying on decaying or- ganic matter for their nutrition.* Phylum Opalinida Once classified as protociliates, then as zooflagellates, their placement here as a separate phylum is meant to draw attention to the enigmatic nature of the opalinids.

The Pearl Oyster

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Engelmann et al. [ 35 ] further demonstrated that earthworm innate immunity depended upon small and large leukocytes (coelomocytes) that synthesized and secreted humoral antimicrobial molecules (e.g., lysenin, fetidin, eiseniapore, coelomic cytolytic factor (CCF), and Lumbricin I). EUPHAUSIACEA, Gloeden, Ivo M. & Montu, Monica, Fundacao Universidade do Rio Grande=20 Malacostraca - Eucarida. Usually the cells of the blastula divide such that the cleavage planes are perpendicular to the surface of the embryo.

Rotifers (Rotifera): Freshwater Fauna of Poland

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By complex ac- tions of wing orientation, insects can hover, fly forward, backward, and sideways, negotiate highly sophisticat- ed aerial maneuvers, and land in any position. Cnidarians have stinging cells called nematocysts or cnidocytes on their tentacles that are poisonous & shoot out like a harpoon to kill or paralyze prey. Sessile opportunists operate in much the same fash- ion as lurking predators do, but they lack the mobility of the latter. The resultant intracellular mem- brane-bounded structure is called a food vacuole.

Classifying Invertebrates (Classifying Living Things)

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Not only do urns effectively cleanse the coelomic fluid, but they also participate in a clotting process when a sipunculan is injured. Origin of the regeneration blastema in polychaete an- nelids. Although sponges are very sensitive to suspended sediment in their environment, they seem to be quite re- sistant to hydrocarbon and heavy metal contamination. SIPUNCULA AND ECHIURA 457 Figure 14.9 These fine SEMS are a result of careful work by Martyn Apley on the development of Urechis caupo. (A) Several embryos about 6 hours old.

Invertebrata

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Crangonoidea and Alpheoidea (Except Glyphocrangonidae and Crangonidae), Christoffersen, Martin Lindsey, Universidade Federal da Paraiba, Joao Pessoa Malacostraca - Eucarida. Pearse (eds.), Reproduction of Marine Invertebrates. Furthermore, scientists at the IINH carry out more specific research projects. More active epibenthic types (e.g., Stichopus, Parastichopus) crawl across the substratum and use their tentacles to ingest sediment and organic detritus (Figure 22.12C).

Aquatic Miniatures (Wild,Wild World of Animals)

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S. de, Museu de Zoologia, Sao Paulo=20 Malacostraca - Eucarida. Oxygenated blood flows from the lophophore into the efferent vessel and from there is distributed to all parts of the trunk. View at Publisher · View at Google Scholar M. Various phagocytic amebocytes are also present in the circulatory fluids of most of these worms. These tiny invertebrates form clouds of aerial plankton that drift unseen through the skies. Recent seminars have focused on my coauthored book, Mating Systems and Strategies.