Massive Growths Research Articles

Recurrent Multiple Symmetric Lipomatosis Affecting the Upper & Lower Limbs: A Case Report

Madelung disease is a rare, metabolic, malignancy-associated and disfiguring condition of unknown etiology, characterized by potentially debilitating neurological, cardiopulmonary, gastric, musculoskeletal and psycho-social complications. Also known as multiple symmetric lipomatosis (MSL), Benign Lipomatosis (BSL), and Launois-Bensaude syndrome, MSL is characterized by the symmetrical growth of subcutaneous non-encapsulated fat deposits, usually around the neck, but in some cases also around shoulders, the upper trunk, chest and limbs, and hip girdle. These abnormal fat deposits may rapidly grow over a few months or slowly enlarge over several years. Expanding fatty deformations may be disabling, have disfiguring aesthetic consequences, and infiltrate or compress adjacent vital structures. This case illustrates that painful, massive growths may also occur around the knees, re-grow post excision, and present with compressive neurological symptoms necessitating further surgical interventions.

Genetic analysis of the invasive alga Didymosphenia geminata in Southern Argentina: Evidence of a Pleistocene origin of local lineages

The diatom Didymosphenia geminata has gained notoriety due to the massive growths which have occurred in recent decades in temperate regions. Different explanations have been proposed for this phenomenon, including the emergence of new invasive strains, human dispersion and climate change. Despite the fact in Argentina nuisance growths began in about 2010, historical records suggest that the alga was already present before that date. In addition, preliminary genetic data revealed too high a diversity to be explained by a recent invasion. Here, we estimate the divergence times of strains from southern Argentina. We integrate new genetic data and secondary, fossil and geological calibrations into a Penalized Likelihood model used to infer 18,630 plausible chronograms. These indicate that radiation of the lineages in Argentina began during or before the Pleistocene, which is hard to reconcile with the hypothesis that a new variant is responsible for the local mass growths. Instead, this suggests that important features of present distribution could be the result of multiple recent colonizations or the expansion of formerly rare populations. The text explains how these two possibilities are compatible with the hypothesis that recent nuisance blooms may be a consequence of climate change.

Morphometry of alien species Pistia stratiotes L. in natural conditions of the Slovak Republic

Pistia stratiotes (water lettuce) is a well-known invasive plant species with distribution especially in tropical and subtropical regions of the world. In the Slovak Republic, the occurrence of alien species P. stratiotes has been recorded since 2007 only in the rivers Malý Dunaj and Cierna voda. The aim of the study was to determine morphometric parameters, density and biomass of P. stratiotes in relation to surface water quality in natural conditions of the Cierna voda river on Podunajska nižina lowland. At four sampling sites, the morphometric parameters of individual plants (535 individuals) were evaluated; density, biomass and dry mass were calculated, too. The largest mother plant had a rosette diameter of 47 cm and a root length of 50 cm. The density of P. stratiotes in massive growths was ca. 380 individuals per 1 m2 and the average biomass 7.3 kg/m2. In sites with thermally abnormal waters in Europe P. stratiotes occurred throughout the year. In the natural conditions of the study area the species grew only half a year and reached smaller dimensions. The obtained values of P. stratiotes morphometric parameters are comparable with species characteristics especially in Europe. Growth density and water quality have a significant impact on plant size.

Zooplankton dynamics in a highly eutrophic microtidal estuary

Mesozooplankton was sampled seasonally in a large microtidal estuary (Peel-Harvey) suffering from massive macroalgal growths and cyanobacterial blooms. Comparisons with other estuaries indicate that eutrophication led to copepod abundance declining and macroalgal-associated species increasing. Mesozooplankton species are almost exclusively autochthonous, i.e. spend entire life cycle within the estuary. Meroplanktonic species are virtually absent because main benthic macroinvertebrate species undergo direct benthic rather than planktotrophic development. There are also few abundant holoplanktonic species. Most species are tychoplanktonic, i.e. benthic and transported into plankton through physical disturbance of sediment. Species number, concentration and Simpson's Index are greater during night than day. Annual cyclical changes in species composition are related closely to changes in salinity. At the most degraded site, nematode concentrations were high and the species number and concentration changed markedly during extreme eutrophication, when oxygen concentrations were low, disrupting annual cyclical changes in species composition.

Effects of Didymosphenia geminata massive growth on stream communities: Smaller organisms and simplified food web structure.

This study aims to contribute to the understanding of the impact of Didymosphenia geminata massive growths upon river ecosystem communities’ composition and functioning. This is the first study to jointly consider the taxonomic composition and functional structure of diatom and macroinvertebrate assemblages in order to determine changes in community structure, and the food web alterations associated with this invasive alga. This study was carried out in the Lumbreras River (Ebro Basin, La Rioja, Northern Spain), which has been affected by a considerable massive growth of D. geminata since 2011. The study shows a profound alteration in both the river community composition and in the food web structure at the sites affected by the massive growth, which is primarily due to the alteration of the environmental conditions, thus demonstrating that D. geminata has an important role as an ecosystem engineer in the river. Thick filamentous mats impede the movement of large invertebrates—especially those that move and feed up on it—and favor small, opportunistic, herbivorous organisms, mainly chironomids, that are capable of moving between filaments and are aided by the absence of large trophic competitors and predators -prey release effect-. Only small predators, such as hydra, are capable of surviving in the new environment, as they are favored by the increase in chironomids, a source of food, and by the reduction in both their own predators and other midge predators -mesopredator release-. This change in the top-down control affects the diatom community, since chironomids may feed on large diatoms, increasing the proportion of small diatoms in the substrate. The survival of small and fast-growing pioneer diatoms is also favored by the mesh of filaments, which offers them a new habitat for colonization. Simultaneously, D. geminata causes a significant reduction in the number of diatoms with similar ecological requirements (those attached to the substrate). Overall, D. geminata creates a community dominated by small organisms that is clearly different from the existing communities in the same stream where there is an absence of massive growths.

Plankton composition, biomass, phylogeny and toxin genes in Lake Big Momela, Tanzania

Lake Big Momela, one of the East African soda lakes in Northern Tanzania characterised by highly saline-alkaline conditions, making them inhospitable to a range of organisms, although supporting massive growths of some adapted planktonic microorganisms that serve as food for birds, such as Lesser Flamingo. The temporal dynamics of plankton, with an emphasis on cyanobacteria, were examined in 2007 using morphological traits and ribosomal genetic markers (16S and 18S rRNA). Cyanobacterial genes encoding for hepatotoxins (mcyE and ndaF) were also screened. Rotifers and copepods dominated the zooplankton, whereas cyanobacteria, such as Anabaenopsis elenkinii and Arthrospira fusiformis dominated the phytoplankton community, and these being related to representatives in other East African soda lakes. The cyanobacteria community also showed distinct seasonal patterns influenced by environmental parameters, mainly salinity, pH and nitrate. Significant positive correlations were found between phytoplankton abundance and nitrate concentrations (r = 0.617, p = 0.033). No signals of the hepatotoxin synthetase genes mcyE and ndaF were retrieved from cyanobacteria during the whole year. In general, our data illustrate the presence of rich planktonic communities, including some unique and potentially endemic cyanobacteria.

Genetic diversity associated with N-cycle pathways in microbialites from Lake Alchichica, Mexico

Author(s): Alcantara-Hernandez, RJ; Valdespino-Castillo, PM; Centeno, CM; Alcocer, J; Merino-Ibarra, M; Falcon, LI | Abstract: Microbialites are an example of complex and diverse microbial assemblages where several metabolic pathways are interconnected for biomass formation coupled to mineral precipitation. Lake Alchichica (Mexico) is an oligotrophic environment where nitrogen (N) and phosphorus alternately limit productivity, and massive microbialite growths are found along the lake's perimeter. Previous studies have described the importance of N2 fixation in these microbialites, although other pathways associated with the N cycle, including denitrification, nitrification and anaerobic ammonium oxidation (anammox), had not been evaluated. This study identified the genetic diversity associated with N cycling in both metagenomic DNA and RNA expression by targeting key genes for nitrogenase (nifH), ammonia monooxygenase (amoA), nitrite oxidoreductase (nxrA, nxrB), hydrazine oxidoreductase (hzo) and nitrite (nirS and nirK) and nitrous oxide (nosZ) reductases. While the genetic potential for N2 fixation, ammonia oxidation, anammox and denitrification was present in the microbialites of Lake Alchichica, the most transcribed pathway was N2 fixation.

Decadal changes in the ichthyofauna of a eutrophic estuary following a remedial engineering modification and subsequent environmental shifts

This study has determined how the characteristics of the ichthyofauna of a large eutrophic microtidal estuary changed, initially in response to major structural remedial modifications, and then, during later years, as the environment became further modified, due mainly to effects of climate change. Data on the ichthyofauna of the Peel-Harvey Estuary, in south-western Australia, were derived firstly by seining seasonally in five regions over two consecutive twelve months (two years) in 2008–10. These data were then collated with those recorded previously using the same sampling regime throughout 1980 and 1981, when massive macroalgal growths were present, and throughout 1996 and 1997, soon after the opening, in 1994, of an artificial, deep and second entrance channel. The latter resulted in greater tidal flushing, consistently high salinities and reduced macroalgal biomass. Ichthyofaunal composition changed significantly overall and in four of the five regions across the three periods. Although increased tidal exchange did not lead to a rise in the number either of those marine species that typically use estuaries as nursery areas (marine estuarine-opportunists) or of those that complete their life cycle within the estuary (estuarine residents), the contributions made by the abundances of the representatives of those two groups to the total catch of fish varied markedly between periods. Those differences were largely responsible for the inter-period changes in species composition. In contrast to the situation with marine estuarine-opportunists, increased tidal exchange and higher salinities resulted in a greater number of marine straggler species entering the system, albeit in low numbers. The ichthyofauna during 1980–81 contained relatively large numbers of species that are typically associated with macrophytes, including marine estuarine-opportunists, e.g. Pelates octolineatus, and estuarine residents e.g. Ostorhinchus rueppellii and Hyporhamphus regularis. Following the opening of the artificial entrance channel, the relative abundances of these three macrophyte-associated species declined, whereas those of species, e.g. the marine estuarine-opportunist Torquigener pleurogramma and estuarine resident Favonigobius lateralis, which typically occur over unvegetated areas and in elevated salinities, increased. By 2008–10, such species had become more abundant, following declines in freshwater discharge and a longer persistence of high salinities, with macrophyte-associated species, e.g. the marine estuarine-opportunists P. octolineatus, Gymnapistes marmoratus and Haletta semifasciata and estuarine resident O. rueppellii, becoming more numerous as macroalgal and seagrass areas became better developed. This study demonstrates the great value of long-term data sets for detecting and predicting the effects of major structural changes and climate change on the faunas of estuaries.

Regional distribution and temporal changes in density and biomass of Didymosphenia geminata in two Mediterranean river basins

This study aimed to strengthen the knowledge of Didymosphenia geminata distribution in Spain, and to determine which environmental variables were related to its regional distribution and temporal changes in growth and production in two Ebro River tributary basins (Iregua and Najerilla¸ La Rioja Region). Living cells of D. geminata were present in 40% of the studied sites of both basins but only four of the sites developed massive growths. The diatom is widely distributed only in mountain areas of both basins (above 690 masl), which have low average annual air temperature (8.27 ± 0.28 oC) and low water Soluble Reactive Phosphorus (SRP) concentration (average value 0.024 ± 0.007 ppm). Massive growths occur in sites with high light intensity, hydrological regulation of river flow and the lowest measured SRP concentrations (below 0.018 ppm SRP). We carried out an intensive spatio-temporal survey in the Lumbreras River (Iregua basin), where the first massive growth was detected in La Rioja Region. The highest cell densities (1.6 × 105 cells cm−2) and biomass values (480 gDWm−2) were recorded in late summer. An increase in solar radiation and slight rise in water temperature were associated with an increase in biomass over time, but always in waters with low SRP concentration, the key factor that enhances massive growth development. The alteration of the natural streamflow in the Lumbreras River by the Pajares Reservoir and the fact that water is discharged from the hypolimnion (which decreases the summer river water temperature) are important factors in understanding why D. geminata shows such an increase in biomass in a Mediterranean river. This paper provides new insights into the importance of different factors controlling D. geminata massive proliferations in the Mediterranean climate zone, where it is assumed that the species should not develop such massive growths, compared to temperate zones where the majority of previous studies have been carried out. We suggest that changing the reservoir management strategy would be a very important contribution to the control of such significant developments.

English

Three new species belonging to the Porcellidiidae are described. A species from NSW possessing massive honeycomb-like dorsal growths of cuticle, and other features not found elsewhere in the family, has been placed in a new genus, Cereudorsum verrucosum gen. et sp. nov. A second species from Queensland, characterized by unusual features of the male antennule, has been placed in a new genus, as Geddesia quadrata gen. et sp. nov. Porcellidium trisetosum Geddes, 1968 does not fit the diagnosis for Porcellidium and is transferred to Geddesia gen. nov., as G. trisetosa (Geddes, 1968) comb. nov. A third species from the Cocos Keeling Islands is unique in having only one seta on the maxillule endopod. It has been referred to a new genus, as Clunia cocosensis gen. et sp. nov. This brings the total number of genera described from eastern coast of Australia to 16. A key to the genera, a list of the apomorphic or unique characters of each genus and a check list of the identifiable species of Porcellidiidae is given. The geographical distribution of species along the east coast of Australia is outlined.

Cyanobacteria: Pioneers of Planet Earth

Cyanobacteria are among the earliest of inhabitants of Planet Earth and their existence can be traced back to 3.8 billion years. Their oxygenic photosynthesis led to the gradual conversion of the Earth‟s atmosphere from an anaerobic to an aerobic one. This change enabled the advent of aerobic organisms that eventually underwent rapid evolution and became the dominant, highly diverse members of the current global biodiversity. Cyanobacteria are ubiquitous in their distribution and are found in all the latitudes from Arctic and Anatarctic regions to the Tropical deserts perhaps reflecting their pioneering habitation of the primitive earth. They are also unique in their ability to simultaneously perform oxygenic photosynthesis and oxygen labile nitrogen fixation. Through these processes they make significant contributions to the Carbon and Nitrogen bio-geochemical cycles, particularly in the deep oceans. The ability of these organisms to fix N2 either independently or in symbiosis with other organisms not only contributes to natural ecosystems but is applied in certain countries particularly for rice cultivation. Their ability to grow in highly polluted environments is also used in the treatment of sewage and industrial effluents. Cyanobacteria are the most efficient among all living organisms in the harvesting of solar energy and are currently looked at as highly attractive candidates for biofuel production. A few species are being used for the production of highly nutritive food supplements. On the negative side, some cyanobacteria form massive growths called „blooms‟ in water bodies and many of them produce toxins harmful to fish, digastric animals and are suspected to be responsible for certain human ailments. Having reviewed most of these aspects of cyanobacteria, it is concluded that knowledge on these little known organisms would be invaluable not only for students, scientists and environmentalists but also for industrialists and policy makers. Key words: cyanobacteria; blue-green algae; algal toxins; biofertilizers; biofuelsDOI: http://dx.doi.org/10.4038/cjsbs.v40i2.3925 CJSBS 2011; 40(2): 71-88

Climate change: a catalyst for global expansion of harmful cyanobacterial blooms

Cyanobacteria are the Earth's oldest known oxygen-evolving photosynthetic microorganisms, and they have had major impacts on shaping our current atmosphere and biosphere. Their long evolutionary history has enabled cyanobacteria to develop survival strategies and persist as important primary producers during numerous geochemical and climatic changes that have taken place on Earth during the past 3.5 billion years. Today, some cyanobacterial species form massive surface growths or 'blooms' that produce toxins, cause oxygen depletion and alter food webs, posing a major threat to drinking and irrigation water supplies, fishing and recreational use of surface waters worldwide. These harmful cyanobacteria can take advantage of anthropogenically induced nutrient over-enrichment (eutrophication), and hydrologic modifications (water withdrawal, reservoir construction). Here, we review recent studies revealing that regional and global climatic change may benefit various species of harmful cyanobacteria by increasing their growth rates, dominance, persistence, geographic distributions and activity. Future climatic change scenarios predict rising temperatures, enhanced vertical stratification of aquatic ecosystems, and alterations in seasonal and interannual weather patterns (including droughts, storms, floods); these changes all favour harmful cyanobacterial blooms in eutrophic waters. Therefore, current mitigation and water management strategies, which are largely based on nutrient input and hydrologic controls, must also accommodate the environmental effects of global warming.

What do we know about Eilat (Red Sea) reef degradation? A critical examination of the published literature

During the last four decades, the coral reef at Eilat, northern Red Sea, has undergone major changes. Increasing impacts from human activities, coupled with those from natural disasters, have set off its current poor state. Here, I critically overview the salient features for Eilat's reef degradation published since the 1960s. Although this reef is one of the most intensively studied small coral reef worldwide, the literature elucidates that the available results are exceedingly fragmented, offering only scanty knowledge for the causes and pathways of the reef deterioration. During the years, 1975–2000, scarcely any reef evaluation had been done and the reef at Eilat was not well characterized to establish baseline data for future evaluations and for analyzing the trends. Even the follow up studies on the extreme low tide episode (occurred during 1970) are limited and localized, and cannot be used as a model case in calibrating Eilat reef status. Natural forces affecting the reef at Eilat are understood only vaguely, and coral assemblages/recruitments, even between neighboring sites, vary markedly in any studied biological-ecological parameter. The importance of the complex networks of interactions between algae, their grazers and corals for structuring coral assemblages, were overlooked, and massive algal growths were mistakenly attributed to anthropogenic impacts alone. Whereas, no long-term study can provide much indication for future prospects, at present, the tourist industry is probably the major cause for reef decline. Surprisingly, the literature further unveils at some sites various ecological properties, such as species diversity and densities of coral species and colonies, similarly to the values recorded decades ago and reveals that the paucity of information has led to conclusions unsubstantiated by robust sets of experiments. At this stage, therefore, decisive conclusions pertaining to the causes and pathways of Eilat reef degradation cannot be reached. Four future prospectuses are outlined, including the need for implementation of active restoration measures.

High-Sulfur Coals in the Eastern Kentucky Coal Field

The Eastern Kentucky coal field is notable for relatively low-sulfur, [open quotes]compliance[close quotes] coals. Virtually all of the major coals in this area do have regions in which higher sulfur lithotypes are common, if not dominant, within the lithologic profile. Three Middle Pennsylvanian coals, each representing a major resource, exemplify this. The Clintwood coal bed is the stratigraphically lowest coal bed mined throughout the coal field. In Whitley County, the sulfur content increase from 0.6% at the base to nearly 12% in the top lithotype. Pyrite in the high-sulfur lithotype is a complex mixture of sub- to few-micron syngenetic forms and massive epigenetic growths. The stratigraphically higher Pond Creek coal bed is extensively mined in portions of the coal field. Although generally low in sulfur, in northern Pike and southern Martin counties the top one-third can have up to 6% sulfur. Uniformly low-sulfur profiles can occur within a few hundred meters of high-sulfur coal. Pyrite occurs as 10-50 [mu]m euhedra and coarser massive forms. In this case, sulfur distribution may have been controlled by sandstone channels in the overlying sediments. High-sulfur zones in the lower bench of the Fire Clay coal bed, the stratigraphically highest coal bed considered here, aremore » more problematical. The lower bench, which is of highly variable thickness and quality, generally is overlain by a kaolinitic flint clay, the consequence of a volcanic ash fall into the peat swamp. In southern Perry and Letcher counties, a black, illite-chlorite clay directly overlies the lower bench. General lack of lateral continuity of lithotypes in the lower bench suggests that the precursor swamp consisted of discontinuous peat-forming environments that were spatially variable and regularly inundated by sediments. Some of the peat-forming areas may have been marshlike in character.« less

Shifts in the Effects of Tuft-weaving Midges on Filamentous Algae

-During summer low-flow periods massive growths of filamentous green algae (dominated by Cladophora glomerata) in the Eel River of Northern California become infested with chironomid larvae that weave the algae into retreats, or Field experiments suggest that these midges (primarily Pseudochironomus richardsoni) have negative early effects, and positive later effects on the biomass of algae they inhabit. During initial colonization and tuft construction by midges, weight loss of Cladophora and associated epiphytes in stream enclosures increased with increasing midge densities. In an in situ incubation experiment, chlorophyll a content and final damp weight of Cladophora and epiphytes were higher with old, feces-filled tufts, or with nitrate fertilizer, and were lower in controls or with new midge tufts. These results suggest that tuft-weaving midges have complex effects on algae they inhabit that change with the ontogeny of midges and the age of the retreats they construct.

Spirogyra species and accompanying algae from pools and ditches in The Netherlands

In ditches and moorland pools zygnematacean algae, especially Spirogyra, make up an important and often dominant component of floating algae. Of the total number of 60 Spirogyra species as yet recorded in The Netherlands, 47 species were recorded in ditches and pools. Sirogonium was represented by only one species, S. sticticum (Engl. Bot.) Wille, and Mougeotia and Zygnema by seven and six species, respectively. In hardwater ditches, especially at sites with relatively low pollution, Spirogyra forms a richly diversified component with up to ∼ 20 species per site. At hardwater sites with appreciable pollution, Spirogyra is suppressed or replaced by massive growths of algae such as Cladophora, Vaucheria, Enteromorpha or Hydrodictyon. At low alkaline and slightly acid sites, the number of species per site is considerably lower. Under conditions with pH values < 5, Spirogyra does not occur and is replaced by Mougeotia, Zygnema, Klebsormidium, Microspora and some others. The periodicity of Spirogyra species was studied. A peak in spore production occurs in the second half of May and the first half of June. Spores were more frequently observed in hardwater habitats than in low-alkaline environments. Most species have wide ranges of occurrence; 22 species were found in low alkaline and slightly acid habitats, but most of these species are not restricted to such environments. Presumably they are adapted to nutrient-poor conditions. In eutrophic hardwater ditches, Spirogyra granulata Jao and S. singularis Nordst. appeared to be very tolerant to pollution. Species such as Spirogyra nitida (Dillw.) Link and S. majuscula Kütz. seem to indicate seepage of groundwater in otherwise nutrient-rich environments.

Cyanobacterial Toxins in Water

Cyanobacteria (blue-green algae) commonly occur in fresh- and brackish waters and may produce massive annual growths as a consequence of nutrient enrichment from natural waters, agricultural fertilizer run-off, or from domestic/industrial effluents. The cyanobacterial species which dominate these growths typically belong to the genera which produce toxins. Cyanobacterial toxins cause fatal poisonings of agricultural livestock, wild animals, birds and fish on a world-wide basis. The involvement of the toxins in human health problems has also been inferred in several countries and their presence in drinking water sources is of interest to the drinking water industry. The occurrence and properties of cyanobacterial toxins are discussed here. New methods are being developed for the purification of the toxins and for their recovery and quantification from waters. These include the use of chemical, cytotoxicity and immunological methods to complement the mouse bioassay which has hitherto been used in cyanobacterial toxin studies with laboratory cultures and water samples. Information on the regulation of cyanobacterial toxin production and on the possible biological significance of the toxins in aquatic environments is also presented. A greater awareness of cyanobacterial toxins in waters destined for human use is required.

SEASONAL CHANGES IN THE DIATOM FLORA IN A SMALL RESERVOIR WITH SPECIAL REFERENCE TOSKELETONEMA POTAMOS

Seasonal changes in the phytoplankton of the small eutrophic River Rott in Bavaria have been studied over a 2 year period. Total phytoplankton peaks in May and then several times later in the summer and autumn, before declining to a minimum in winter. Diatoms are usually the dominant algae, most of them belonging to centric genera. In a reservoir along the Rott, Skeletonema potamos is abundant during August and September, sometimes in concentrations of 106ml−1; S. potamos also occurs in the riverine sections of the Rott, but in smaller numbers. Silicate concentrations do not appear to be significantly affected by these massive growths of S. potamos but are reduced during the growth of more heavily silicified centric diatoms. Brief comparisons are made with other river systems, especially with respect to 5. potamos.

Rhodoliths and coralliths of Muri Lagoon, Rarotonga, Cook Islands

Free-living massive and branching spheroidal growths (about 5 cm diameter) of calcareous red algae (rhodoliths) and corals (coralliths) occur in abundance on the sea bed of shallow Muri Lagoon on Rarotonga's reef flat. The rhodoliths are composed of one or more species of Neogoniolithon, Lithophyllum, Tenarea, and Porolithon; the coralliths are Pavona varians (Verrill) and Porites lutea (Milne-Edwards and Haime). Muri Lagoon is the only area on Rarotonga's reef flat that is sheltered by reef islands from ocean waves. The tidal currents, which are predominantly unidirectional in Muri Lagoon, are concentrated by the reef islands into channels through which sand and gravel sediment is regularly transported. However, these prevailing currents do not normally roll the rhodoliths and coralliths. The results of field experiments on the pick-up velocity of the various types of spheroidal structure, combined with observations on growth histories of massive coralliths as revealed by the non-concentric nature of skeletal density banding, indicate that the rhodoliths and coralliths may remain static for periods up to several months yet maintain a complete envelope of living tissue. This downward survival may depend on the strong currents. Not only is the water flushing through the upper millimetre or so of the sediment substrate, but it is also capable of moving the sand and gravel grains which laterally support the rhodoliths and coralliths so that no one point of a spheroidal structure is in direct contact with the substrate for a fatal length of time. Massive rhodoliths have a high preservation potential as discrete spheroidal structures; in contrast, branching rhodoliths and coralliths are prone to fragmentation, and massive coralliths grow into stable microatolls. We conclude that a similar assemblage of rhodoliths, coralliths and microatolls in the fossil record may be indicative of the former existence of contemporary reef flat islands.

Carcinoma of the anal sac glands in ranch mink.

During a 14-year period, carcinoma of the anal sac apocrine glands was found in 52 pastel and 8 sapphire mink (Mustela vison) kept for studies on slow viral diseases. The pastel mink varied in age from 72 to 135 months (mean age 108 months), the sapphire mink from 63 to 100 months (mean age 81 months). All but one pastel mink were females. The primary tumor varied in size from masses that caused bulges in the perineum to those that were found only after microscopic examination of the anal sac glands. Although the primary tumor grew mainly by expansion with little local infiltration, 41 of the 60 tumors had metastasized to the regional lymph nodes and sometimes also to more distant sites. The striking propensity of the carcinoma to metastasize while still small, even microscopic, often resulted in massive secondary growths, notably in the iliac lymph nodes. Hypercalcemia did not accompany the carcinoma. Its varied microscopic appearance included solid, glandular, squamous cell, and spindle or round cell components. Combinations of them formed mixed or complex histologic patterns, no doubt largely attributable to neoplastic proliferation of myoepithelial cells and squamous metaplasia of the apocrine gland epithelium. Although its cause remains obscure, the carcinoma appeared to arise from small foci of hyperplastic apocrine glands, sometimes in relation to both anal sacs. The tumor is a common and distinctive expression of neoplasia in older ranch mink.