• Invertebrates
  • Notodontidae & Oenosandridae (Lepidoptera) (World Catalogue

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    Because the anus is located anteriorly on the dorsal side of the body, the digestive tract is basically U- shaped, although highly coiled (Figure 14.3A,B). A life cycle featuring alternation of sexual, swimming medusae with benthic asexual polyps is typical of many cnidarians. LOPHOPHORATES 29 1 (A) BrachiopodaPhoronida Ectoprocta 2 3 1 4 5 7 8 9 (B) BrachiopodaPhoronida Ectoprocta 6 Figure 21.23 Lophophorate phylogeny. (A) Without assumptions about the ancestral form, other than the ori- gin of the lophophore (1), a trichotomy results where each group arises independently from the ancestor. (B) Assum- ing a phoronid-like ancestor, the ectoprocts and bra- chiopods form a clade defined in part by the reduction of the circulatory system (2).
  • Invertebrates
  • Intrinsic Immunity (Current Topics in Microbiology and

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    ISOPODA - ONISCIDEA, Souza Kury, Leila Aparecida, Universidade de Sao Paulo, Sao Paulo To purchase a volume, send a check for US$50.00 in the name of the "Fundacao Universitaria Jose Bonifacio" to: Ms. The rhabdome is two-layered, and the distal retinular cells form a ring around the proximal cone tip. The details of the arrangement of the canals vary among different groups; the following description applies to the arrangement in a cydippid. And, even if true, this does not necessarily imply that in the pre-fusion con- dition the ommatidia would have been tetrapartite.
  • Invertebrates
  • Encyclopedia of Texas Seashells: Identification, Ecology,

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    Archives available at http://www.vims.edu/~jeff/archive.htm =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-= ------------------------------ Date: Tue, 26 Jan 1999 10:14:18 -0500 (EST) From: Lisa Rodrigues Subject: CRUST-L: Sexing Hermit Crabs Hello - I am presently trying to determine the sexes of the tropical hermit crab, Clibanarius tricolor. Peel your “skin” like a reptile, dissect a fish, make origami jumping frogs, compare amphibian and reptile eggs by feeling tapioca and grapes, and more!
  • Invertebrates
  • Barnacles in Nature and in Myth

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    The keystone of phylogenetic systematics is the recognition that all homologues de- fine monophyletic groups at some level. Segmental ganglia on the ventral nerve cord in xiphosurans and scorpions serve the opisthosomal appendages, muscles, and sense or- gans. Eversion of the proboscis (Figure 11.6) is accom- plished by contraction of the muscles around the rhyn- chocoel; this increases the hydrostatic pressure within the rhynchocoel itself, squeezing on the proboscis and causing its eversion.
  • Invertebrates
  • Evolutionary Developmental Biology of Invertebrates 5:

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    Influence of patch-burn grazing on the ecological integrity of tallgrass prairie streams. Anterior–posterior limb movements are accom- plished in two basic ways. This group includes the largest of all living invertebrates, the giant squid, with body and tentacle lengths exceeding 20 m. The lab will be worth a total of 150 points, constituting 30% of your invertebrate zoology grade. In asconoid and leuconoid sponges, the blastula is called coeloblastula as it does not possess a mouth but has a blastocoel and flagella on the surface of the body.
  • Invertebrates
  • Zooplankton & Phytoplankton: Types, Characteristics &

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    Some (e.g., Leptodora, Bythotreptos) are predators on other cladocerans. Since insects are the most diverse group of organisms on Earth, and since all insects harbor numerous parasites, it is fair to say that the most common mode of life on Earth is that of an insect parasite. Both treat the evolution of ambulacral rays (arms) as con- vergent, arising once in the crinoids and again in the asteroids and ophiuroids; cladogram A indicates that this condition is also convergent in the asteroids and ophi- uroids.
  • Invertebrates
  • Minibeast Babies (Acorn: Comparing Minibeasts)

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    Moles are impressive diggers and can tunnel through 20m of earth in a day. Cladistic analysis of metazoan phyla and the place- ment of fossil problematica. Dur- ing mating, two flukes align themselves such that the cirrus of each can be inserted into the female orifice of the other. We have little knowledge of their life histories and they, like microsporans, are characterized on the basis of spore structure. Apparently these loose cells reattach to the gut wall after they have “fed.” It has been suggested that upon re- attachment these errant cells first pass their digested food contents to the fixed cells of the gut wall, then assume an excretory function by picking up metabolic wastes, de- taching again and being eliminated via the anus.
  • Invertebrates
  • Scorpions of Medical Importance

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    Patterns of feeding and activity in deposit-feeding holothurians and echinoids (Echinodermata) from a shallow back-reef lagoon, Discovery Bay, Jamaica. Begin the exercise with observations of general anatomy. But the fact is, unicellularity mandates that a high surface area-to-volume ratio be maintained by restricting shape and size. Metamerism increases the efficiency of body movement by allowing the effect of muscle contraction to be extremely localized, and it makes possible the development of greater complexity in general body organization.
  • Invertebrates
  • C. elegans Atlas

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    The epidermis is usually richly supplied with gland cells, many of which are in- volved in mucus production, particularly on the pro- boscis and collar of enteropneusts and on the tentacles of pterobranchs. The general body surface has various minute hairlike structures developed from individual cells. Geological Society of America and University of Kansas Press. The longi- tudinal furrows divided the cephalon into a median glabella and lateral cheeks.
  • Invertebrates
  • Aquatic Oligochaetes: Proceedings of the 7th International

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    The color of light varies from deep blue (shrimp and dinoflagellates) to blue-green or green (ostracods and tunicates), to yellow and even red (fire- flies). For this reason, vertebrates can achieve larger sizes than invertebrates, and on average vertebrates are, in fact, larger. These bristles allow the earthworm to move and to burrow into soil. The maxillae and labium of these insects have well de- veloped leglike palps that help them hold food in place, while powerful mandibles cut off and chew bite-sized pieces.