Invertebrate Pathology: Non-communicable Diseases

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All are slow-moving predators on other small invertebrates. Princeton University Press, Princeton, New Jersey. 1039 pp. Tilting the animal causes the sta- tolith to press more heavily on the downside balancers, and the resulting stimulus elicits a vigorous beating of the corresponding comb rows to right the body. During the summer, blackfly larvae and pupae comprise eighty percent of the beaver dam fauna and occur in great numbers, similar to what one finds at lake outlets (Clifford et al. 1993).

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Intertidal Invertebrates of the Central California Coast: S

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Food is moved through the digestive tube by peristaltic action of the muscular gut wall and by gener- al body movements associated with locomotion. The arms circle the mouth, which is directed upward, away from the substrate. Porifera: Sudden sperm release by tropical Demospongiae. One gametic nucleus in each conjugant remains in its “par- ent” conjugant while the other is transferred to the other conjugant via a cytoplasmic connection formed at the point of joining.

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Freshwater Mussels of Florida

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Die systematische Einteilung des Tierreiches. The Invertebrates, Vol. 3, Acanthocephala, Aschelminthes, and Entoprocta. The nervous sys- tem of cephalopods is the most sophisticated of all mol- luscs, if not all invertebrates. In a cladogram of species, the line segments represent the places where anagenesis (microevolution) is taking place within a given species. Females tend to reject the advances of other males after they have consumed one mate. The elongate stomodeum lies on the oral–aboral axis of the body.

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Spineless Creatures (Primary Science Mini-Unit)

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University of Michigan Press, Ann Arbor. [A wonderful, timeless little volume.] Scholtz, G. 1995. It is said that Caroline was badly treated by her husband (the Prince Regent, later George IV), and that she was herself a lady of ques- tionable fidelity. Flagellate phylogeny: A study in conflicts. The recep- tor sites of amphids are derived from modified cilia, but motile cilia do not occur in nematodes. Unique Tssues (not all) – i. nervous – impulse conducTon ii. muscle – moTlity (during one stage of life cycle) d.

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Waiting for Aphrodite: Journeys into the Time Before Bones

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Hickman taught at Washington and Lee from 1967 until his retirement in 1993. That would be a great source of information! In other words, they ANIMAL DEVELOPMENT, LIFE HISTORIES, AND ORIGINS 115 Figure 4.20 A version of the gonocoel theory (schemat- ic cross sections). (A) The condition in flatworms, which have mesodermally derived gonads leading to ventral gonopores. (B) The condition in nemerteans, which have serially arranged gonadal masses leading to laterally placed gonopores. (C) The condition in polychaetes, in which the linings of the gonads have expanded to produce coelomic spaces with coelomoducts to the outside.

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Land Snails and Slugs of Russia and Adjacent Countries

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Credit is due under the terms of this license that can reference both the New World Encyclopedia contributors and the selfless volunteer contributors of the Wikimedia Foundation. Innovative studies examining the linear arrangement of mitochondrial genes by Boore and his colleagues also support a Hexapoda + Crustacea sister-group relationship through the finding of unique gene arrangements. Cambridge University Press, Cambridge pp. 137–160.

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An Encyclopaedia of Indian Monogenoidea

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Always use freshly collected pond water or rain water; chlorinated tap water will usually kill hydra as well as the smaller creatures upon which they feed. A large ventral nerve cord also bears ganglia. This is due to the simple nervous system which is organized as a nerve net, each nerve cell conducting impulses over a short distance. The 72,000 de- scribed species are thought to represent only 5–10 percent of the actual diversity.

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FROGS & TOADS OF THE WORLD

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These are just a few of the many, many, many animals that are called invertebrates. Nearly all ticks are blood-sucking parasites on the body surfaces of reptiles or mammals. Anomalocarids were once thought to represent an extinct phylum of segment- ed animals, but are now regarded by many workers as primitive crustaceans dating back to the Ediacaran. (D) Wiwaxia, a Burgess Shale animal with no clear affinity to any known metazoan phylum (although some workers regard it as a polychaete annelid). (E) Nectocaris, another creature that has yet to be classified into any known phy- lum (despite its strong chordate-like appearance). (F) Dinomischus, a stalked creature with a U-shaped gut and with the mouth and anus both placed on a radially symmetrical calyx.

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Invertebrate Embryology;

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In members of the classes Hydrozoa, Scypho- zoa, and perhaps Cubozoa, the capsule is covered by a hinged lid, or operculum, which is thrown open when the cnida discharges. They are common in subterranean groundwater ecosystems of caves, the ma- jority being stygobionts—obligatory groundwater species characterized by reduction or loss of eyes, pig- mentation, and occasionally appendages. Crustaceana 21: 165–175. [See Schminke 1976 for an opposing view.] Bowman, T. The anus is ventral at the trunk–tail junction.

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Cephalopods of the world: An annotated and illustrated

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No separate taxon was estab- lished for these worms until 1828, when DeBlainville in- troduced the name Sipunculida and allied the group with certain parasitic helminths. Clades are monophyletic branches that may undergo various degrees of diversifica- tion. In this species, all three thoracic segments appear to have had “articulated” thoracic lobes. *Unspecialized coxal exites can be seen on the legs of some living archaeognathans (bristletails) and in numerous extinct hexapods. (B) (A) (C) UNCORRECTED PAGE PROOFS dorsally to a position below the tergum.

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