The stomatogastric nervous system of the reptantian Decapoda Crustacea, particularly the small isolated stomatogastric ganglion containing the 25-30 motor neurons that control the muscles of the gastric mill and the pyloric filter of the stomach, is an important preparation for research in comparative neurophysiology. Unfortunately there are no comprehensive descriptions of the neuromuscular system of the stomach in these animals. Therefore, since the stomatogastric motor neurons are identified by reference to the muscles they innervate, it has been difficult to identify neurons within or between species. The most important features for classifying the muscles of the decapod stomach are the ossicles to which the muscles attach. In the latter part of the last century Mocquard demonstrated that the stomach ossicles of the decapods could be compared in different groups despite the large variations from group to group. A summary of Mocquard’s (1883) classification scheme, with some modifications, is given. The scheme recognizes 33 ossicles in seven categories (cardiac gastric mill, I—VII; lateral supporting cardiac ossicles, VIII-XV ; ossicles of the cardio-pyloric valve, XVI-XVIII; supporting ossicles of the dorsal pyloric stomach, XIX -XXI; supporting ossicles of the ventral pylorus and ampullae, XXII-XXVII; supra-ampullary ossicles, XXVIII-XXX ; supporting ossicles of the lateral pylorus, XXXI-XXXIII). Where necessary, comments are then made on the ossicles of the three divergent species studied, the blue crab, Callinectes sapidus (Brachyura); the lobster, Homarus americanus (Macrura) and the spiny lobster Panulirus argus (Palinura). Most of the thirty-three ossicles are found in each of the species, but there are some major differences between species. Callinectes , for example, has the most complex ossicle system and Panulirus the most reduced.

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For drinking water, the people of Bangladesh used to rely on surface water, which was often contaminated with bacteria causing diarrhea, cholera, typhoid, and other life-threatening diseases. To reduce the incidences of these diseases, millions of tubewells were installed in Bangladesh since independence in 1971. This recent transition from surface water to groundwater has significantly reduced deaths from waterborne pathogens; however, new evidence suggests disease and death from arsenic (As) and other toxic elements in groundwater are affecting large areas of Bangladesh. In this evaluation, the areal and vertical distribution of As and 29 other inorganic chemicals in groundwater were determined throughout Bangladesh. This study of 30 analytes per sample and 112 samples suggests that the most significant health risk from drinking Bangladesh's tubewell water is chronic As poisoning. The As concentration ranged from < 0.0007 to 0.64 mg/L, with 48% of samples above the 0.01 mg/L World Health Organization drinking water guideline. Furthermore, this study reveals unsafe levels of manganese (Mn), lead (Pb), nickel (Ni), and chromium (Cr). Our survey also suggests that groundwater with unsafe levels of As, Mn, Pb, Ni, and Cr may extend beyond Bangladesh's border into the four adjacent and densely populated states in India. In addition to the health risks from individual toxins, possible multimetal synergistic and inhibitory effects are discussed. Antimony was detected in 98% of the samples from this study and magnifies the toxic effects of As. In contrast, Se and Zn were below our detection limits in large parts of Bangladesh and prevent the toxic effects of As.

Background: The World Health Organization (WHO) released the fourth edition of Guidelines for Drinking-Water Quality in July 2011. In this edition, the 400-µg/L drinking-water guideline for manganese (Mn) was discontinued with the assertion that because “this health-based value is well above concentrations of manganese normally found in drinking water, it is not considered necessary to derive a formal guideline value.”Objective: In this commentary, we review the WHO guideline for Mn in drinking water—from its introduction in 1958 through its discontinuation in 2011.Methods: For the primary references, we used the WHO publications that documented the Mn guidelines. We used peer-reviewed journal articles, government reports, published conference proceedings, and theses to identify countries with drinking water or potential drinking-water supplies exceeding 400 µg/L Mn and peer-reviewed journal articles to summarize the health effects of Mn.Discussion: Drinking water or potential drinking-water supplies with Mn concentrations > 400 µg/L are found in a substantial number of countries worldwide. The drinking water of many tens of millions of people has Mn concentrations > 400 µg/L. Recent research on the health effects of Mn suggests that the earlier WHO guideline of 400 µg/L may have been too high to adequately protect public health.Conclusions: The toxic effects and geographic distribution of Mn in drinking-water supplies justify a reevaluation by the WHO of its decision to discontinue its drinking-water guideline for Mn.

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BackgroundMore than 60,000,000 Bangladeshis are drinking water with unsafe concentrations of one or more elements.ObjectivesOur aims in this study were to evaluate and improve the drinking water testing and treatment plans for western Bangladesh.MethodsWe sampled groundwater from four neighborhoods in western Bangladesh to determine the distributions of arsenic, boron, barium, chromium, iron, manganese, molybdenum, nickel, lead, antimony, selenium, uranium, and zinc, and to determine pH.ResultsThe percentages of tube wells that had concentrations exceeding World Health Organization (WHO) health-based drinking water guidelines were 78% for Mn, 48% for U, 33% for As, 1% for Pb, 1% for Ni, and 1% for Cr. Individual tube wells often had unsafe concentrations of both Mn and As or both Mn and U. They seldom had unsafe concentrations of both As and U.ConclusionsThese results suggest that the ongoing program of identifying safe drinking water supplies by testing every tube well for As only will not ensure safe concentrations of Mn, U, Pb, Ni, Cr, and possibly other elements. To maximize efficiency, drinking water testing in Bangladesh should be completed in three steps: 1) all tube wells must be sampled and tested for As; 2) if a sample meets the WHO guideline for As, then it should be retested for Mn and U; 3) if a sample meets the WHO guidelines for As, Mn, and U, then it should be retested for B, Ba, Cr, Mo, Ni, and Pb. All safe tube wells should be considered for use as public drinking water supplies.

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