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Veliger Stages Although the term “veliger” is often used popularly to refer to all planktonic (i.e., floating in water column) stages in the life cycle, strictly speaking this term does not include the trochophore stage, but rather refers only to the stages that possess a velum, i.e., the straight-hinged stage ( Veliger densities typically peak in midsummer in North America, with lower densities present in spring and autumn. The larvae are then referred to as D-shaped or straight-hinged veligers, since the body side where the hinge is forming is straight while the open valve side is rounded. el.erdc.usace.army.mil /zebra/zmis/zmishelp4/veliger_stages.htm   (413 words)

Greenwich Bay After these stages, the larva is called a veliger, because it has a velum (literally, a "curtain"), a large sail-shaped organ that extends from the small larval shell. Larval stages include the straight-hinge veliger (i), the umbonate veliger (j), and the pediveliger (k). The straight-hinge veliger (also known as the "D-hinge" veliger) is given its name from the shape of the larval shell. seagrant.gso.uri.edu /G_Bay/HabitatEco/Shellfishing/quahog_dev.html   (503 words)

Examination of the Potential of Chlorine Dioxide for Use in Zebra Mussel Veliger Control Dreissena polymorpha (zebra mussel) veligers were treated with various concentrations of chlorine dioxide and exposed at several time intervals to determine the effectiveness of this oxidant as a veliger control agent. Veliger mortality was determined based on observations of veliger movement. Typical criteria for the determination of mortality was expanded to include four categories; veliger actively swimming internal musculature movement, no internal musculature movement observed, however not necessarily indicating a mortality and obviously a mortality. www.sgnis.org /publicat/120.htm   (389 words)

Microscopic observations of larval Ostrea circumpicta in brood chambers Journal of Shellfisheries Research - Find ...   (Site not responding. Last check: 2007-10-10) The digestive system of the larvae, including the mouth, esophagus, stomach, digestive gland, and intestine, was identifiable in histologic preparations, indicating that the veliger larvae in the brood chamber were capable of feeding using the velum and cilia. Veliger larvae in the chamber are characterized by velum covered with cilia that are used for locomotion and feeding (Elston 1999, Chaparro et al. Swimming veliger larvae are often observed in suprabrachial or infrabranchial chambers (Chaparro et al. www.findarticles.com /p/articles/mi_m0QPU/is_2_23/ai_n6276405   (896 words)

Apical Sensory Organ in Larvae of the Patellogastropod Tectura scutum -- Page 202 (1): 6 -- The Biological Bulletin The apical sensory organ in veliger larvae of a patellogastropod, pit, in veligers at the onset of ontogenetic torsion. The apical sensory organ of a gastropod veliger is a receptor for settlement cues. www.biolbull.org /cgi/content/full/202/1/6   (7032 words)

Developmental Stages of the Geoduck Clam The anatomical terminology used in describing the location of structures of the veliger larvae is illustrated in Fig. The characteristic feature of veliger larvae is the velum, a large ciliated organ that predominates the ventral surface of the larvae and is used for locomotion and the acquisition of food. The velum and associated cilia are retracted in all the veliger larvae illustrated histologically in this report. www-sci.pac.dfo-mpo.gc.ca /geoduck/develop_e.htm   (1081 words)

Lake Champlain Zebra Mussel Monitoring Stations   (Site not responding. Last check: 2007-10-10) To calculate veliger densities, a net efficiency of 100% was assumed and the volume of water filtered was estimated based on the length of tow and net aperture. Veliger identification was verified under a compound microscope with assistance of VTDEC Biomonitoring and Aquatic Studies Section taxonomists. If veligers were too abundant to count in full (greater than 100 per sample), the sample was diluted quantitatively as necessary and three 1 ml subsamples were extracted into 1 ml Sedgewick-Rafter cells, counted, and used to estimate the density of the entire sample. www.anr.state.vt.us /dec/waterq/lakes/htm/lp_lczebramon.htm   (1365 words)

Gabaldon > Excerpts > RAH > Roach Veliger turned his back, hunching his shoulders as he raised his voice over the noise of the fan. Veliger had a fresh cigarette between his fingers; he swiveled halfway around in his chair, leaned back, and blew a long stream of imaginary smoke toward the ceiling. Veliger leaned over my shoulder to peer into the pot, where the roach rode its whirlpool to a merciful oblivion, round and round and round, still kicking. www.its.caltech.edu /~gatti/gabaldon/excerpts/rah/rah_roach.html   (1899 words)

VELIGER LARVA HOME PAGE A variety of neurotransmitters/modulators may be found in the veliger larval nervous system. Recent studies suggest that interaction between neuronal systems utilizing these neuroactive substances and with associated sensory structures, adds a higher degr ee of complexity (and perhaps capability) to the larval nervous system than would be suggested by the relatively small number of neurons present and cursory examination of its apparently simple morphology. The veliger is the typically descibed larva of the inverterbate phylum known as the Mollusca, and is characteristic of the molluscan classes, Gastropoda and Bivalvia. www.auburn.edu /academic/science_math/old_zoology/veliger.html   (2068 words)

Veliger This slide shows several veliger larvae that are found in many gastropods and bivalves. The larvae (which develop from a ciliated, free-swimming trochophore) have the beginnings of a foot, shell and mantle. In many molluscs the trochophore is passed in the egg, and the veliger hatches to become the only free-swimming stage. bioweb.uwlax.edu /zoolab/Table_of_Contents/Lab-5b/Veliger/veliger.htm   (75 words)

MOLLUSCA Later Stages of Development: A typical gastropod veliger is formed from the gastrula. In older veligers the alimentary tract becomes more complex; a triangular mouth, ciliated oesophagus, large ciliated stomach and a narrow intestine with one coil may be seen. At hatching, the veliger is enclosed in a curved shell; the large, two lobed velum, which protrudes from it, propels the free-swimming larva through the water. www.mbl.edu /BiologicalBulletin/EGGCOMP/pages/62.html   (567 words)

Re: What is the life cycle of a sea snail? What type of eyes do they have? A very important event in a snails life occurs when it is a veliger type of larva,ususally shortly before settling and growing to be a n adult snail. The body and shell of the veliger twist through 180 degrees relative to the foot and head. All land snails and some sea snails have direct development, with both the trochophore and veliger stages being passed inside the egg, and the young being born as mini-adults crawling out of the adult shell. www.madsci.org /posts/archives/may99/927203558.Zo.r.html   (546 words)

Veliger - Wikipedia, the free encyclopedia Veliger are the free-swimming, planktonic larvae of certain marine and fresh-water univalve mollusks, or gastropods as well as some bivalves (Dreissena sp.). Veliger of sea hare Dolabrifera dolabrifera, two cilia visible. The Veliger, Publication of the California Malacozoological Society en.wikipedia.org /wiki/Veliger   (120 words)

Aquascope|Facts|Mussel veliger   (Site not responding. Last check: 2007-10-10) While they rest as in the picture above, they pull in their velum between the two shell halves, but when they swim, the cirria are easily seen. The common mussel for example has two pelagic larva stages, while with the oyster, the larva has reached the veliger stage before the female releases the larva into the water. During the summer and autumn, mussel veliger dominate to such an extent so that other veliger are difficult to see. www.vattenkikaren.gu.se /fakta/arter/mollusca/bivalvia/bivaveli/bivavee.html   (258 words)

Article of the Month: Ballad of the Veliger No problem having weight if you slither across the sea floor, in fact it is an advantage, it helps to stop you being knocked off your perch by waves, currents and over-energetic fish. It is for this very reason, namely trying to keep from sinking with their heavy shell, that veligers developed the enormously elaborate wing of beating cilia. In some species this wing and its double row of cilia is so active that it looks as if the young snail larva is surrounded by a hoop of flickering fire. www.imagequest3d.com /pages/articles/articleofmonth/veliger/veligerpoem.htm   (804 words)

Webvita Sickel, J.B. Gluttonous feeding behavior in the Rhabdocoel, Macrostomum sp., induced by juveniles of the Asiatic clam, Corbicula fluminea. Variations in zebra mussel (Dreissena polymorpha) veliger densities throughout 1996 at Dam 52 on the lower Ohio River. Annual variations in zebra mussel (Dreissena polymorpha) veliger densities throughout 1996 at Dam 52 on the lower Ohio River. campus.murraystate.edu /academic/faculty/jim.sickel/jsickel.htm   (1196 words)

Graduate_Research_dlloyd Clearly visible is the feeding/swimming structure or velum, the foot, the larval shell, and the digestive tract. These snails have a two-part life cycle; carnivorous benthic adults that lay egg capsules, and the planktonic larvae that first develop into trochophores and later become veliger larvae. They hatch competent to feed and swim, especially being able to control their depth. faculty.fullerton.edu /dzacherl/Graduate_Research_dlloyd.html   (213 words)

Natural Resources Commission - Lake Michigan and Other Navigable Waters   (Site not responding. Last check: 2007-10-10) Periodic updates of the map shall be distributed to personnel of the Department of Natural Resources and other critical state agencies. Other appropriate safeguards shall be taken to prevent the transfer of zebra mussels to uncontaminated waters if work is performed in a geographical area containing zebra mussels. High risk areas include waterways with confirmed sightings of adults or veligers, waters contiguous to these areas, and sites frequently visited by boaters after they operate watercraft on contaminated waters. www.in.gov /nrc/policy/zebra.html   (1256 words)

Publications of Dr. Richard L. Squires   (Site not responding. Last check: 2007-10-10) Squires, R. L., 1993, New occurrences of the large gastropod Campanile from the Paleocene and Eocene of the Pacific coast of North America. Squires, R. L, 1993, The gastropod Terebra santana Loel and Corey, 1932, from the lower Miocene Vaqueros Formation, southern California, belongs in the cerithiid genus Clavocerithium s.s.The Veliger, v. Saul, L. R., Squires, R. L., and Goedert, J. new genus of cryptic lucinid bivalve from lower Cenozoic cold seeps of the Pacific slope of North America: Journal of Paleontology, v. www.csun.edu /~hcgeo004/pubs.html   (3580 words)

NORM Oyster Larval Abundance at Restoration Sites Oyster embryos or veliger larvae are free swimming for approximately 21 days before they settle onto clean oyster shell and recruit to the bottom. Plankton tows will be conducted near restoration sites to evaluate the abundance of oyster veligers throughout the spawning season. These estimates of oyster veligers per volume of water will be combined with estimates of broodstock abundance, demographics, fecundity, and recruit abundance for the same site to evaluate the contribution made by the broodstock on a particular reef to the overall availability of oyster veligers within a habitat. www.vims.edu /mollusc/NORM/NORMmonelement/moneloyveliger.htm   (124 words)

Primar Filtration-Zebra Mussel Filters-Home Primar Filtration's patented filters are designed to effectively screen out all material as small as 50 microns in size, including the Zebra Mussel veliger which at its setting stage is 100 microns in size. To certify our claims, we commissioned ACRES International, a scientific and engineering company, to conduct an independent analysis of our filter. The results were remarkable: ACRES concluded that our ceramic filter is 100% effective in screening out all life forms of Zebra Mussels. www.primarfiltration.com   (98 words)

Bibliography - Generic Names Taxonomic study on Meretrix (Mollusca: Bivalvia) from Thailand. Yoshida, H. On the full-grown veligers and early young-stage of Venerupis (Amygdala) philippinarum (Adams and Reeve). Yoshida, H. Studies on larvae and young shells of industrial bivalves in Japan. peet.fmnh.org /BibliographyS_Z.html   (2041 words)

NORM Graph Gallery Rappahannock River Rappahannock River, VA Drumming Ground Reef: Veliger abundance Rappahannock River, VA Drumming Ground Reef: Recruit abundance Rappahannock River, VA Parrot's Rock Reef: Veliger abundance www.vims.edu /mollusc/NORM/NORMdatahub/NORMGGRapp.htm   (140 words)

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