Guide to Identification of Marine and Estuarine

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The female gametocyte forms a single macrogamete; the male gametocyte typically undergoes multiple fission to produce several motile, flagellated microgametes within the gut of the mosquito (5). Cells of the presumptive areas under- go immediate organogenesis by direct proliferation. The first pair, called salivary glands, lies within the prosoma and produces much of the digestive juice used in preliminary external diges- tion. The echin- oderms capitalized on radial symmetry and on the vari- ous functional aspects of their ossicle-based skeleton and water vascular system.

Encyclopedia of Tidepools and Rocky Shores (Encyclopedias of

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Have children cut out pictures of animals and glue them onto a piece of construction paper with a line down the middle having one side labeled vertebrates and on the other side labeled invertebrates. The nerve net is concentrated around the mouth. In echinoderms, the coelomocytes occupy perivisceral coelomic cavities, the water-vascular system, and the haemal system besides the connective tissue and tissues of various organs [ 7, 8 ]. The embryo grows quickly, elongates, and hatches as a juvenile chaetognath.

Patterns of Variation in Wasps of the Genus Therion

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Explication de systéme nerveux des animaux in- vertébrés. One of the most interesting examples of partheno- genesis occurs in honeybees; in these animals the queen is fertilized by one or more males (drones) at only one period of her lifetime, in her “nuptial flight.” The sperm are stored in her seminal receptacles. The unique version of spiral cleavage in acoels lends support to this idea, and preliminary phylogenetic analyses suggest their placement between the diploblastic phyla (Cnidaria, Ctenophora) and the triploblasts.

Marine Prosobranch Gastropods from Oceanic Islands off

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Most nematocysts contain several different toxins that vary in activity and strength, but as a class of chem- icals they are all potent biological poisons capable of subduing large, active prey, including fish. Much of their success has resulted from the apparent evolutionary plasticity of their di- morphic life histories, the alternation between polypoid and medusoid phases. Furthermore, the ventral epithelium can be temporarily invaginated, presumably for feeding (Figure 4.16E).

Pathobiology of invertebrate vectors of disease: [papers]

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Gastrozooids capture and ingest prey and provide energy and nutrients to the rest of the colony, including all the nonfeeding polyps. There are three types of gland cells within the clitel- lum, each secreting a different substance important to reproduction: mucus that aids in copulation; the mater- ial forming the outer casing of the egg capsule (or co- coon); and albumin deposited with the zygotes inside the cocoon. Thus, there is a reasonable assurance of appropriate food sources and other environmental factors for the young.

Animals of Sandy Shores (Naturalists' Handbooks)

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Figure 15.22 depicts some of these events. The structure, development, food relations, repro- duction, and life history of the squid Loligo opalescens Berry. The vessels of the nervous system,” Zeitschrift für Zellforschung und Mikroskopische Anatomie, vol. 77, no. 2, pp. 147–161, 1967. PHYLUM ARTHROPODA: THE MYRIAPODS 3UNCORRECTED PAGE PROOFS Class Pauropoda Nearly microscopic (0.5–1.5 mm); eyeless; 9–11 pairs of legs; some trunk segments partly fused (but not as true diplosegments), plus free telson; without limbs on first trunk segment; mouthparts poorly developed; first maxil- lae fused into a gnathochilarium; second maxillae absent; antennae branched; most without tracheal or circulatory systems; gonopores on third trunk segment; terga often large and extended over two segments; cuticle soft, uncal- cified.

New Zealand Inventory of Biodiversity: Vol. 3: Kingdoms

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Phylum Granuloreticulosa (Foraminifera and Their Kin) The phylum Granuloreticulosa contains about 40,000 de- scribed species, many of which are fossils. The reduced but functional digestive tract of adult nematomorphans is a simple elongate tube running the length of the body (Figure 12.26E). In the Heliozoa, it has been observed that the ax- opodia are used to roll among algae and in at least one genus, Sticholonche, they appear to be used as tiny oars.

Shells: A Guide to the Jewels of the Sea

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At the risk of disappointing all of you, I regret to announce that there are none. Regulative development in a spiralian embryo as shown by cell deletion experiments on the acoel Childia. I almost got to go to Lake Baikal several years ago to work on amphipods there, and this fluoring question was one we were going to look at (with Jerry Barnard, piggybacking on National Geographic--funding fell through). The di- gestive tract is largely nonfunctional, and nematomorphans appear to lack any structural excreto- ry mechanisms.

Microscopic Anatomy of Invertebrates, Chelicerate Arthropoda

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The oligochaetes represent the primitive clitel- late condition. The 55 species and 25 genera are divided between two orders. The age and relationships of the major animal phyla. We will be adding to these throughout the unit as homework. Monarch butterflies ( Danaus plexippus ) and Poison arrow frogs ( Dendrobates spp.) are two of the best known examples of such coloration patterns. Fertilization is external, and the embryos hatch as nauplius larvae (see the section on development below).

Essential invertebrate zoology

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Homarus americanus, the “Amer- ican” or Maine lobster, is strictly marine and is the largest living crustacean by weight (the record weight being over 20 kilograms) (Figures 16.27E, H, 16.29B). In nearly all cases, the eye units are covered by a modified section of the cuticle that functions as a cornea. Optical design and evolutionary adaptation in crustacean compound eyes. In the Middle Cambrian (e.g., the Burgess Shale fauna of western Canada and similar deposits else- where; Figure 1.3) polychaetes and tardigrades made their first positive appearances in the fossil record, and the first complete echinoderm skeletons appeared.