THE GROSS AND MICROSCOPIC ANATOMY OF THE DIGESTIVE TRACT OF THE OYSTER CRASSOSTREA VIRGINICA (GMELIN)

1957 ◽  
Vol 35 (3) ◽  
pp. 325-347 ◽  
Author(s):  
Barbara L. Shaw ◽  
Helen I. Battle
Keyword(s):  
Epithelial Cells ◽  
Digestive Tract ◽  
Crassostrea Virginica ◽  
Atlantic Coast ◽  
Dorsal Surface ◽  
Adductor Muscle ◽  
Posterior Chamber ◽  
Microscopic Anatomy ◽  
The North ◽  
Cytoplasmic Processes

The gross and microscopic anatomy of the digestive tract of Crassostrea virginica (Gmelin), the common oyster of commerce of the North Atlantic Coast, is described. The dorsoventrally compressed mouth bounded by two pairs of labial palps leads into a crescentic oesophagus, thence to the anterior chamber of the stomach from which a complex caecum extends into anteriorly and posteriorly directed spiral appendices. The posterior chamber of the stomach bears a chondroid gastric shield and leads into an elongated chamber which is incompletely divided by two typhlosoles into a style-sac and mid-gut. The intestine is divisible into ascending, median, and descending limbs, the latter merging into the rectum which terminates on the dorsal surface of the adductor muscle. Extensively branched tubular digestive diverticula exit from the stomach by a series of ducts along the margin of the caecum and the posterior stomach. The complete digestive tract is lined by a simple columnar epithelium which is ciliated throughout with the exception of the upper lip or fused external palps, the lower side of the gastric shield in the posterior stomach, and the tubules of the digestive diverticula. Mucous secreting and eosinophilic epithelial cells occur in varying numbers along the course of the tract. Phagocytes are present between the lining epithelial cells, among the peripheral collagenous and muscle fibers, as well as in the lumen of the tract. The gastric shield is shown to be intimately attached to the underlying epithelium by a central clip as well as by minute cytoplasmic processes. The anatomical relationships are compared with various lamellibranchs including the Chilean oyster, Ostrea chilensis Philippi; the European oyster, Ostrea edulis L.; and the Portuguese oyster, Gryphea angulata Lamarck.

Population Structure of Eastern Oysters (Crassostrea virginica) Inhabiting the Laguna Madre, Texas, and Adjacent Bay Systems

1994 ◽  
Vol 51 (S1) ◽  
pp. 215-222 ◽  
Author(s):  
Tim L. King ◽  
Rocky Ward ◽  
Earl G. Zimmerman
Keyword(s):  
Crassostrea Virginica ◽  
Atlantic Coast ◽  
Eastern Oyster ◽  
Laguna Madre ◽  
Western Atlantic ◽  
Polymorphic Loci ◽  
Corpus Christi ◽  
The North ◽  
Eastern Oysters ◽  
Fixation Indices

A survey of 16 enzyme systems and two structural proteins, among nine eastern oyster (Crassostrea virginica) populations in and adjacent to Laguna Madre, Texas, identified two genetically differentiated groups and the transition zone between them. The discontinuity in allele frequencies occurred between a reef in Corpus Christi Bay and reefs 26 km away in upper Laguna Madre. Although no fixed allelic differences were observed between populations from either side of the transition area, substantial frequency differences were observed at six gene loci, and both groups exhibited unique alleles. Spatial heterogeneity tests also suggested sizable allele frequency differences, as 8 of 15 polymorphic loci surveyed exhibited heterogeneity. Considerable genetic subdivision was observed, as 14 of 15 polymorphic loci surveyed exhibited significant fixation indices. The mean genetic similarity was 0.898 (range 0.813–0.977). Consequently, oysters inhabiting the Laguna Madre are genetically divergent from oysters inhabiting central and eastern Texas, the north-central and eastern Gulf of Mexico, and the western Atlantic coast. Thus, these groups should be considered as discrete management units, and the patterns of genetic exchange investigated. If eastern oysters inhabiting the Laguna Madre, Texas, are unique, they warrant protection.

scholarly journals Phylogeography in an “oyster” shell provides first insights into the genetic structure of an extinct Ostrea edulis population

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Sarah Hayer ◽  
Dirk Brandis ◽  
Alexander Immel ◽  
Julian Susat ◽  
Montserrat Torres-Oliva ◽  
...  
Keyword(s):  
Large Scale ◽  
Wadden Sea ◽  
Atlantic Coast ◽  
Phylogenetic Reconstruction ◽  
Oyster Shell ◽  
Glacial Refugia ◽  
Late Nineteenth Century ◽  
Ostrea Edulis ◽  
Geographic Ranges ◽  
The North

AbstractThe historical phylogeography of Ostrea edulis was successfully depicted in its native range for the first time using ancient DNA methods on dry shells from museum collections. This research reconstructed the historical population structure of the European flat oyster across Europe in the 1870s—including the now extinct population in the Wadden Sea. In total, four haplogroups were identified with one haplogroup having a patchy distribution from the North Sea to the Atlantic coast of France. This irregular distribution could be the result of translocations. The other three haplogroups are restricted to narrow geographic ranges, which may indicate adaptation to local environmental conditions or geographical barriers to gene flow. The phylogenetic reconstruction of the four haplogroups suggests the signatures of glacial refugia and postglacial expansion. The comparison with present-day O. edulis populations revealed a temporally stable population genetic pattern over the past 150 years despite large-scale translocations. This historical phylogeographic reconstruction was able to discover an autochthonous population in the German and Danish Wadden Sea in the late nineteenth century, where O. edulis is extinct today. The genetic distinctiveness of a now-extinct population hints at a connection between the genetic background of O. edulis in the Wadden Sea and for its absence until today.

scholarly journals V.—Geology of the Channel Islands

1878 ◽  
Vol 5 (2) ◽  
pp. 79-86 ◽  
Author(s):  
J. A. Birds
Keyword(s):  
Atlantic Coast ◽  
Channel Islands ◽  
The North ◽  
The World ◽  
Almost All ◽  
Extended View ◽  
European Coast

In the most extended view, the Channel Islands may be regarded as fragments and relics of the Eastern or European coast of the Atlantic, reckoning from the North Cape to Cape St. Vincent, and including the Western shores of Scotland and Ireland, and the promontories of Pembrokeshire and Cornwall. They are excellent illustrations, says Professor Ansted, “of those spurs and tongues of porphyritic rock, of which almost all the promontories of the Atlantic coast of Europe consist.” Very small and insignificant specks indeed they seem in such a length of coast, stretching from lat. 37° to 72°, or upwards of 2000 miles; but there is a charm in such wide horizons, and it is a very allowable indulgence so to connect the little with the great, and to consider the position of such little specks in relation to the geography of Europe; one might almost as well say, of the world at large.

scholarly journals Centennial-to-millennial hydrologic trends and variability along the North Atlantic Coast, USA, during the Holocene

2014 ◽  
Vol 41 (12) ◽  
pp. 4300-4307 ◽  
Author(s):  
Paige E. Newby ◽  
Bryan N. Shuman ◽  
Jeffrey P. Donnelly ◽  
Kristopher B. Karnauskas ◽  
Jeremiah Marsicek
Keyword(s):  
North Atlantic ◽  
Atlantic Coast ◽  
The Holocene ◽  
The North ◽  
The North Atlantic

scholarly journals Índices Parasitários de Brevimulticaecum sp. (Nematoda: Heterocheilidae) Em Potamotrygon motoro (Chondrichthyes: Potamotrygonidae) Capturados no Arquipélago do Bailique, Macapá

2021 ◽  
Vol 24 (5-esp.) ◽  
pp. 511-515
Author(s):  
Antonio Carlos Freitas Souza ◽  
Cecile Souza Gama ◽  
Anderson Luiz Pena da Costa ◽  
Jociel Ferreira Costa ◽  
Diego Carvalho Viana
Keyword(s):  
Digestive Tract ◽  
The State ◽  
Average Intensity ◽  
Behavioral Differences ◽  
Host Association ◽  
The North ◽  
Spiral Valve ◽  
Average Abundance ◽  
Parasitic Parameters

O número de nematódeos descritos em elasmobrânquios é relativamente pequeno, sendo encontrados majoritariamente no trato digestório. Apesar de alguns relatos descritos, a literatura a respeito ainda é considerada escassa principalmente sobre a associação parasita-hospedeiro. Diante disso, o objetivo deste trabalho foi avaliar os índices parasitários de larvas Brevimulticaecum sp. na válvula espiral de Potamotrygon motoro provenientes do arquipélago do Bailique, em Macapá no estado do Amapá, Brasil. Registrou-se em 20,41% das raias coletadas a presença de larvas de Brevimulticaecum sp., sendo a intensidade média de 20,10 larvas/peixe e a abundância média de 4,10. São poucos os registros deste parasito em peixes no Brasil, sendo que já foi relatada sua ocorrência no estômago de P. motoro e Potamotrygon falkneri. As diferenças entre os parâmetros parasitários podem ser um indicador de alimentação e/ou diferenças comportamentais entre os sexos. Este é o primeiro estudo sobre nematóides de potamotrigonídeos na região Norte, ampliando o conhecimento da biodiversidade desta região.   Palavras-chave: Helmintos. Nematoda; Elasmobrânquio. Válvula Espiral.   Abstract The number of nematodes described in elasmobranchs is relatively small, being found mostly in the digestive tract. Despite some reports described, the literature on this subject is still considered scarce, mainly on the parasite-host association. Therefore, the objective of this work was to evaluate the parasitic indices of Brevimulticaecum sp. the Potamotrygon motoro spiral valve from the Bailique archipelago, in Macapá in the state of Amapá, Brazil. Larvae of Brevimulticaecum sp. Were recorded in 20.41% of the rays collected, with an average intensity of 20.10 larvae / fish and an average abundance of 4.10. There are few records of this parasite in fish in Brazil, and its occurrence in the stomach of P. motoro and Potamotrygon falkneri has been reported. Differences between parasitic parameters can be an indicator of diet and / or behavioral differences between genders. This is the first study on potamotrigonid nematodes in the North, expanding knowledge of this region's biodiversity.   Keywords: Helminths. Nematoda. Elasmobranchs. Spiral Valve.

scholarly journals Watching the war against Iraq through pan-Arab satellite TV

2003 ◽  
Vol 9 (1) ◽  
pp. 26-31 ◽  
Author(s):  
Mohamed El-Bendary
Keyword(s):  
Arab World ◽  
Middle Eastern ◽  
Atlantic Coast ◽  
News Coverage ◽  
Al Jazeera ◽  
The West ◽  
Satellite Television ◽  
The North ◽  
Satellite Channels ◽  
Flow Of Information

It was the first Gulf War in 1991 which led to the satellite television explosion in the Arab world. Arabs then knew about Iraq’s invasion of Kuwait through CNN. Today, Arab satellite channels reach almost every Arab capital and many Middle Eastern and African nations — from Mauritania on the Atlantic coast to Iran in the east, from Syria in the north to Djibouti in the south. This battle for the airwaves and boom in satellite channels in the Arab world has become both a tool for integration and dispersion. It is raising a glimpse of hope that the flow of information will no longer be pouring from the West to the East, but from the East to the West. Questions, however, remain about the credibility of news coverage by Arabic networks like the maverick Qatar-based al-Jazeera and whether Arab journalists adhere to journalistic norms upheld in the West.

The North Atlantic Coast Fisheries Arbitration

1911 ◽  
Vol 11 (1) ◽  
pp. 1 ◽  
Author(s):  
Edwin M. Borchardt
Keyword(s):  
North Atlantic ◽  
Atlantic Coast ◽  
The North ◽  
The North Atlantic
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