Galashiels
Galashiels is a town in the Scottish Borders and historic county of Selkirkshire, on the Gala Water river. The name is shortened to "Gala"; the town, with a population of around 12,600, is a major commercial centre for the Borders region. The town is known for textile making, is the location of Heriot-Watt University's School of Textiles and Design, Galashiels Academy and the main campus of Borders College at Netherdale. To the west of the town there is an ancient earthwork known as Catrail, it extends many miles south and its height and width varies. There is no agreement about the purpose of the earthwork. There is another ancient site on the north-western edge of the town, at Torwoodlee, an Iron Age hill fort, with a Broch known as Torwoodlee Broch built in the western quarter of the hill fort, overlapping some of the defensive ditches of the original fort; the Romans destroyed the broch in AD 140. The town's coat of arms shows two foxes reaching up to eat plums from a tree, the motto is Sour Plums pronounced in Scots as soor plooms.
This is a reference to an incident in 1337 when a raiding party of English soldiers were picking wild plums close to the town and were caught by Scots who came across them by chance and slaughtered them all. On a hillside to the north of the town, Buckholm Tower is a prominent structure which dates back to 1582 and replaced an earlier tower built on the same site but destroyed around 1570. In 1599 Galashiels received its burgh Charter, an event celebrated every summer since the 1930s by the "Braw Lads Gathering", with riders on horseback parading through the town; the Paton Street drill hall was completed in the late 19th century. Galashiels' population grew fast through the textile trade with several mills. A connection with the town's mill history, the Mill Lade, still links the town from near the site of mills at Wheatlands Road, to Netherdale, via Wilderhaugh, Bank Street, the Fountain and next to the Tesco/retail development Street. Galashiels has an oceanic climate; however due to its elevated position and distance from the sea it has colder winters and warmer summers than coastal places such as Edinburgh and Eyemouth.
Snow is much more common in winter, covers the ground for an average of 38 days a year in an average winter. The following sports clubs are based in Galashiels: Gala Cricket Club Gala Fairydean Rovers Gala RFC Galashiels Golf Club Robert Burns wrote two poems about Galashiels, "Sae Fair Her Hair" and "Braw Lads"; the latter is sung by some of the townsfolk each year at the Braw Lads Gathering. Sir Walter Scott built his home, just across the River Tweed from Galashiels; the Sir Walter Scott Way, a long-distance path from Moffat to Cockburnspath, passes through Galashiels. There is some good-hearted rivalry between some of the Galashiels townsfolk and those of other border towns Hawick, the next largest town in the Scottish Borders. Galashiels' citizens refer to their rival as dirty Hawick while the'Teries' retort that Galashiels's residents are pail merks because their town was the last to be plumbed into the mains water system and so residents had to rely on buckets as toilets. Galashiels was home to the author of the famous Scottish song, "Coulters Candy".
Robert Coltart was a weaver in the town, but made confectionery in nearby Melrose. The song was created as an advertisement, hence was renamed as "Sugar Candy" when played by the BBC; the song is better known by the first line of its chorus - "Ally, ally bally bee". Coltart died in 1890; the 1985 Marillion hit single Kayleigh was inspired by events that took place in Galashiels as the band's lead singer Fish spent some time in the town in his earlier years. In 2012 the Scottish Borders Council undertook work to revamp the Market Square with lyrics of the song inscribed into the paving slabs. Fish reopened the square on completion that year. In 1969, the historic Waverley Line which connected the Scottish Borders to the national rail network was closed as part of a wider series of cuts to British Railways; the closure led to a campaign for a return of rail to the region. Following years of campaigning, in 2006, the Waverley Railway Act was passed by the Scottish Parliament, which authorised a partial restoration of the service.
The new Borders Railway, which links Galashiels with Edinburgh, saw four new stations built in Midlothian and three in the Scottish Borders. For most of the route the original line was followed with 30 miles of new railway line built; the project is estimated to cost £294 million and was completed in September 2015, with the formal opening on 9 September by the Queen. Trains from Galashiels railway station run every half-hour going down to hourly in the evening and on Sundays. Journey times between Tweedbank and Edinburgh take less than one hour; the town has a opened Interchange building which replaces the old bus station, is situated next to the railway station. It has a café, allowing travelers and commuters to relax prior to their bus or train journey, upstairs has office space which can be leased to businesses and organizations, it has full toilet and baby changing facilities, a travel helpdesk. The following are listed by Scottish Borders Council as being in the Galashiels area and are catchment schools for Galashiels Academy.
Primary schools Balmoral Primary Burgh Primary Clovenfords Primary Fountainhall Primary, Midlothian Glendinning Terrace Primary Heriot Primary, Midlothian Langlee Primary Stow Primary St Margaret's Roman Catholic
Fauna
Fauna is all of the animal life present in a particular region or time. The corresponding term for plants is flora. Flora and other forms of life such as fungi are collectively referred to as biota. Zoologists and paleontologists use fauna to refer to a typical collection of animals found in a specific time or place, e.g. the "Sonoran Desert fauna" or the "Burgess Shale fauna". Paleontologists sometimes refer to a sequence of faunal stages, a series of rocks all containing similar fossils; the study of animals of a particular region is called faunistics. Fauna comes from the name Fauna, a Roman goddess of earth and fertility, the Roman god Faunus, the related forest spirits called Fauns. All three words are cognates of the name of the Greek god Pan, panis is the Greek equivalent of fauna. Fauna is the word for a book that catalogues the animals in such a manner; the term was first used by Carl Linnaeus from Sweden in the title of his 1745 work Fauna Suecica. Cryofauna refers to the animals that live in, or close to, cold areas.
Cryptofauna are the fauna. Infauna are benthic organisms that live within the bottom substratum of a water body within the bottom-most oceanic sediments, rather than on its surface. Bacteria and microalgae may live in the interstices of bottom sediments. In general, infaunal animals become progressively smaller and less abundant with increasing water depth and distance from shore, whereas bacteria show more constancy in abundance, tending toward one million cells per milliliter of interstitial seawater. Epifauna called epibenthos, are aquatic animals that live on the bottom substratum as opposed to within it, that is, the benthic fauna that live on top of the sediment surface at the seafloor. Macrofauna are soil organisms which are retained on a 0.5 mm sieve. Studies in the deep sea define macrofauna as animals retained on a 0.3 mm sieve to account for the small size of many of the taxa. Megafauna are large animals of any particular time. For example, Australian megafauna. Meiofauna are small benthic invertebrates that live in both freshwater environments.
The term meiofauna loosely defines a group of organisms by their size, larger than microfauna but smaller than macrofauna, rather than a taxonomic grouping. One environment for meiofauna is between grains of damp sand. In practice these are metazoan animals that can pass unharmed through a 0.5 – 1 mm mesh but will be retained by a 30–45 μm mesh, but the exact dimensions will vary from researcher to researcher. Whether an organism passes through a 1 mm mesh depends upon whether it is alive or dead at the time of sorting. Mesofauna are macroscopic soil animals such as nematodes. Mesofauna are diverse. Microfauna are microscopic or small animals. Other terms include avifauna, which means "bird fauna" and piscifauna, which means "fish fauna". Linnaeus, Carolus. Fauna Suecica. 1746 "Biodiversity of Collembola and their functional role in the ecosystem"
Charles Lapworth (journalist)
Charles Lapworth was a socialist activist and film promoter. He was born in Willenhall, Staffordshire on 13 June 1878, the son of a coal miner. Lapworth toured with Eugene V. Debs in 1908, speaking about socialism in Britain, he returned to Britain to stand in Sheffield Brightside at the January 1910 general election for the Social Democratic Party, but took only 4.7% of the vote. He toured Italy with his wife, investigating the socialist movement there, wrote Tripoli and the Young Italy with Helen Zimmern. In 1912, Lapworth again returned to Britain. Although he increased circulation, he upset its publisher, George Lansbury, by criticising Philip Snowden, Lansbury himself replaced Lapworth as editor in late 1913. Lapworth worked as night editor of the Daily Mail for a short time, before returning to the United States, which he toured with his family in an early Ford. In 1918, he interviewed Charlie Chaplin, worked with him as a writer and consultant on A Dog's Life. During the 1920s, he edited the Los Angeles Graphic newspaper, acted as Sam Goldwyn's agent in London.
In 1925, he joined the board of Gainsborough Pictures, where he wrote film scripts including The Sea Urchin and the original story of the early Hitchcock movie, The Mountain Eagle. He worked as production manager with the short-lived Société Générale des Films, who made The Passion of Joan of Arc. In 1931, he returned as editor of Film Quarterly. Among his other projects was the co-ownership of the Rye Courier, a small newspaper based in Rye, New York. In 1942, Lapworth launched the first newspaper in the city, he died in Los Angeles, California on 26 October 1951. He left a wife and two children
Ordovician
The Ordovician is a geologic period and system, the second of six periods of the Paleozoic Era. The Ordovician spans 41.2 million years from the end of the Cambrian Period 485.4 million years ago to the start of the Silurian Period 443.8 Mya. The Ordovician, named after the Celtic tribe of the Ordovices, was defined by Charles Lapworth in 1879 to resolve a dispute between followers of Adam Sedgwick and Roderick Murchison, who were placing the same rock beds in northern Wales into the Cambrian and Silurian systems, respectively. Lapworth recognized that the fossil fauna in the disputed strata were different from those of either the Cambrian or the Silurian systems, placed them in a system of their own; the Ordovician received international approval in 1960, when it was adopted as an official period of the Paleozoic Era by the International Geological Congress. Life continued to flourish during the Ordovician as it did in the earlier Cambrian period, although the end of the period was marked by the Ordovician–Silurian extinction events.
Invertebrates, namely molluscs and arthropods, dominated the oceans. The Great Ordovician Biodiversification Event increased the diversity of life. Fish, the world's first true vertebrates, continued to evolve, those with jaws may have first appeared late in the period. Life had yet to diversify on land. About 100 times as many meteorites struck the Earth per year during the Ordovician compared with today; the Ordovician Period began with a major extinction called the Cambrian–Ordovician extinction event, about 485.4 Mya. It lasted for about 42 million years and ended with the Ordovician–Silurian extinction events, about 443.8 Mya which wiped out 60% of marine genera. The dates given are recent radiometric dates and vary from those found in other sources; this second period of the Paleozoic era created abundant fossils that became major petroleum and gas reservoirs. The boundary chosen for the beginning of both the Ordovician Period and the Tremadocian stage is significant, it correlates well with the occurrence of widespread graptolite and trilobite species.
The base of the Tremadocian allows scientists to relate these species not only to each other, but to species that occur with them in other areas. This makes it easier to place many more species in time relative to the beginning of the Ordovician Period. A number of regional terms have been used to subdivide the Ordovician Period. In 2008, the ICS erected a formal international system of subdivisions. There exist Baltoscandic, Siberian, North American, Chinese Mediterranean and North-Gondwanan regional stratigraphic schemes; the Ordovician Period in Britain was traditionally broken into Early and Late epochs. The corresponding rocks of the Ordovician System are referred to as coming from the Lower, Middle, or Upper part of the column; the faunal stages from youngest to oldest are: Late Ordovician Hirnantian/Gamach Rawtheyan/Richmond Cautleyan/Richmond Pusgillian/Maysville/Richmond Middle Ordovician Trenton Onnian/Maysville/Eden Actonian/Eden Marshbrookian/Sherman Longvillian/Sherman Soudleyan/Kirkfield Harnagian/Rockland Costonian/Black River Chazy Llandeilo Whiterock Llanvirn Early Ordovician Cassinian Arenig/Jefferson/Castleman Tremadoc/Deming/Gaconadian The Tremadoc corresponds to the Tremadocian.
The Floian corresponds to the lower Arenig. The Llanvirn occupies the rest of the Darriwilian, terminates with it at the base of the Late Ordovician; the Sandbian represents the first half of the Caradoc. During the Ordovician, the southern continents were collected into Gondwana. Gondwana started the period in equatorial latitudes and, as the period progressed, drifted toward the South Pole. Early in the Ordovician, the continents of Laurentia and Baltica were still independent continents, but Baltica began to move towards Laurentia in the period, causing the Iapetus Ocean between them to shrink; the small continent Avalonia separated from Gondwana and began to move north towards Baltica and Laurentia, opening the Rheic Ocean between Gondwana and Avalonia. The Taconic orogeny, a major mountain-building episode, was well under way in Cambrian times. In the early and middle Ordovician, temperatures were mild, but at the beginning of the Late Ordovician, from 460 to 450 Ma, volcanoes along the margin of the Iapetus Ocean spewed massive amounts of carbon dioxide, a greenhouse gas, into the atmosphere, turning the planet into a hothouse.
Sea levels were high, but as Gondwana moved south, ice accumulated into glaciers and sea levels dropped. At first, low-lying sea beds increased diversity, but glaciation led to mass extinctions as the seas drained and continental shelves became dry land. During the Ordovician, in fact during the Tremadocian, marine transgressions worldwide were the greatest for which evidence is preserved; these volcanic island arcs collided with proto North America to form the Appalachian mountains. By the end of the Late Ordovician the volcanic emissions had stopped. Gondwana had by that time neared the South Pole and was glaciated
University of Aberdeen
The University of Aberdeen is a public research university in Aberdeen, Scotland. It is an ancient university founded in 1495 when William Elphinstone, Bishop of Aberdeen and Chancellor of Scotland, petitioned Pope Alexander VI on behalf of James IV, King of Scots to establish King's College, making it Scotland's third-oldest university and the fifth-oldest in the English-speaking world. Today, Aberdeen is ranked among the top 200 universities in the world and is ranked within the top 30 universities in the United Kingdom. In the 2019 Times Higher Education University Impact Rankings, Aberdeen was ranked 31st in the world for impact on society. Aberdeen was named the 2019 Scottish University of the Year by The Times and Sunday Times Good University Guide; the university as it is comprised was formed in 1860 by a merger between King's College and Marischal College, a second university founded in 1593 as a Protestant alternative to the former. The university's iconic buildings act as symbols of wider Aberdeen Marischal College in the city centre and the crown steeple of King's College in Old Aberdeen.
There are two campuses. Although the original site of the university's foundation, most academic buildings apart from the King's College Chapel and Quadrangle were constructed in the 20th century during a period of significant expansion; the university's Foresterhill campus is next to Aberdeen Royal Infirmary and houses the School of Medicine and Dentistry as well as the School of Medical Sciences. Together these buildings comprise one of Europe's largest health campuses; the annual income of the institution for 2017–18 was £219.5 million of which £56.1 million was from research grants and contracts, with an expenditure of £226.8 million. Aberdeen has 13,500 students from undergraduate to doctoral level, including many international students. An abundant range of disciplines are taught at the university, with 650 undergraduate degree programmes offered in the 2012-13 academic year. Many important figures in the field of theology were educated at the university in its earlier history, giving rise to the Aberdeen doctors in the 17th century and prolific enlightenment philosopher Thomas Reid in the 18th.
Five Nobel laureates have since been associated with Aberdeen. The first university in Aberdeen, King's College, formally The University and King's College of Aberdeen, was founded in February 1495 by William Elphinstone, Bishop of Aberdeen, Chancellor of Scotland, a graduate of the University of Glasgow drafting a request on behalf of King James IV to Pope Alexander VI resulting in a Papal Bull being issued; the university, modelled on that of the University of Paris and intended principally as a law school, soon became the most famous and popular of the Scots seats of learning due to the prestige of Elphinstone and his friend, Hector Boece, the first principal. Despite this founding date, teaching did not start for another ten years, the University of Aberdeen celebrated 500 years of teaching and learning in 2005. Following the Scottish Reformation in 1560, King's College was purged of its Roman Catholic staff but in other respects was resistant to change. George Keith, the fifth Earl Marischal was a moderniser within the college and supportive of the reforming ideas of Peter Ramus.
In April 1593 he founded a second university in Marischal College. It is possible the founding of another college in nearby Fraserburgh by Sir Alexander Fraser, a business rival of Keith, was instrumental in its creation. Aberdeen was unusual at this time for having two universities in one city: as 20th-century University prospectuses observed, Aberdeen had the same number as existed in England at the time. Marischal College offered the Principal of King's College a role in selecting its academics, but this was refused - the first blow in a developing rivalry. Marischal College, in the commercial heart of the city, was quite different in outlook. For example, it was more integrated into the life of the city, such as allowing students to live outwith the College; the two rival colleges clashed, sometimes in court, but in brawls between students on the streets of Aberdeen. As the institutions put aside their differences, a process of attempted mergers began in the 17th century. During this time, both colleges made notable intellectual contributions to the Scottish Enlightenment.
Both colleges supported the Jacobite rebellion and following the defeat of the 1715 rising were purged by the authorities of their academics and officials. The nearest the two colleges had come to full union was as the "Caroline University of Aberdeen", a merger initiated by Charles I of Scotland in 1641. Following the civil conflicts of the Wars of the Three Kingdoms, a more complete unification was attempted following the ratification of Parliament by Oliver Cromwell during the interregnum in 1654; this united university survived until the Restoration whereby all laws made during this period were rescinded by Charles II and the two colleges reverted to independent status. Charles I is still recognised as one of the university's founders, due to his part in creating the Caroline University and his benevolence towards King's College. Further unsuccessful suggestions for union were brought about throughout the 18th and early 19th centuries; the two universities in Aberdeen merged on 15 September 1860 in accord
Roderick Murchison
Roderick Impey Murchison, 1st Baronet KCB DCL FRS FRSE FLS PRGS PBA MRIA was a Scottish geologist who first described and investigated the Silurian system. Murchison was born at Muir of Ord, Ross-shire, the son of Kenneth Murchison, his wealthy father died in 1796, when Roderick was four years old, he was sent to Durham School three years and the Royal Military College, Great Marlow to be trained for the army. In 1808 he landed with Wellesley in Galicia, was present at the actions of Roliça and Vimeiro. Subsequently under Sir John Moore, he took part in the retreat to Corunna and the final battle there. After eight years of service Murchison left the army, married Charlotte Hugonin, the only daughter of General Hugonin, of Nursted House, Hampshire. Murchison and his wife spent two years in mainland Europe in Italy, they settled in Barnard Castle, County Durham, England in 1818 where Murchison made the acquaintance of Sir Humphry Davy. Davy urged Murchison to turn his energy to science, after hearing that he wasted his time riding to hounds and shooting.
Murchison became fascinated by the young science of geology and joined the Geological Society of London, soon becoming one of its most active members. His colleagues there included Adam Sedgwick, William Conybeare, William Buckland, William Fitton, Charles Lyell and Charles Darwin. Exploring with his wife, Murchison studied the geology of the south of England, devoting special attention to the rocks of the north-west of Sussex and the adjoining parts of Hampshire and Surrey, on which, aided by Fitton, he wrote his first scientific paper, read to the Geological Society of London in 1825. Turning his attention to Continental geology, he and Lyell explored the volcanic region of Auvergne, parts of southern France, northern Italy and Switzerland. A little with Sedgwick as his companion, Murchison attacked the difficult problem of the geological structure of the Alps, their joint paper giving the results of their study is a classic in the literature of Alpine geology. Murchison was an opponent of Charles Darwin's theory of evolution.
He supported successive creation. In 1831 he went to the England–Wales border, to attempt to discover whether the greywacke rocks underlying the Old Red Sandstone could be grouped into a definite order of succession; the result was the establishment of the Silurian system under which were grouped, for the first time, a remarkable series of formations, each replete with distinctive organic remains other than and different from those of the other rocks of England. These researches, together with descriptions of the coalfields and overlying formations in South Wales and the English border counties, were embodied in The Silurian System; the establishment of the Silurian system was followed by that of the Devonian system, an investigation in which Murchison assisted, both in the south-west of England and in the Rhineland. Soon afterwards Murchison projected an important geological campaign in Russia with the view of extending to that part of the Continent the classification he had succeeded in elaborating for the older rocks of western Europe.
He was accompanied by Édouard de Verneuil and Count Alexander von Keyserling, in conjunction with whom he produced a work on Russia and the Ural Mountains. The publication of this monograph in 1845 completes the first and most active half of Murchison's scientific career, he was elected a Foreign Honorary Member of the American Academy of Arts and Sciences in 1840. In 1846 he was knighted, in the same year he presided over the meeting of the British Association at Southampton. During the years of his life a large part of his time was devoted to the affairs of the Royal Geographical Society, of which he was in 1830 one of the founders, he was president 1843–1845, 1851–1853, 1856–1859 and 1862–1871, he served on the Royal Commission on the British Museum. The chief geological investigation of the last decade of his life was devoted to the Highlands of Scotland, where he wrongly believed he had succeeded in showing that the vast masses of crystalline schists supposed to be part of what used to be termed the Primitive formations, were not older than the Silurian period, for that underneath them lay beds of limestone and quartzite containing Lower Silurian fossils.
James Nicol recognised the fallacy in the Murchison's extant theory and propounded his own ideas, in the 1880s these were superseded by the correct theory of Charles Lapworth, corroborated by Benjamin Peach and John Horne. Their subsequent research showed that the infraposition of the fossiliferous rocks is not their original place, but had been brought about by a gigantic system of dislocations, whereby successive masses of the oldest gneisses, have been exhumed from below and thrust over the younger formations. In 1855 Murchison was appointed director-general of the British Geological Survey and director of the Royal School of Mines and the Museum of Practical Geology in Jermyn Street, London, in succession to Sir Henry De la Beche, the first to hold these offices. Official routine now occupied much of his time, but he found opportunity for the Highland researches just alluded to, for preparing successive editions of his work Siluria, meant to present the main features of the original Silurian System together with a digest of subsequent discoveries of those that showed the extension of the Silurian classification into other countries.
In 1845, whilst visiting Carclew in Cornwall, he met several Cornish miners who were going to Australia. Believing that there might be gold there he asked them to s
Graptolithina
Graptolithina is a subclass of the class Pterobranchia, the members of which are known as graptolites. These organisms are colonial animals known chiefly as fossils from the Middle Cambrian through the Lower Carboniferous. A possible early graptolite, Chaunograptus, is known from the Middle Cambrian. One analysis suggests. Studies on the tubarium of fossil and living graptolites showed similarities in the basic fusellar construction and it is considered that the group most evolved from a Rhabdopleura-like ancestor; the name graptolite comes from the Greek graptos meaning "written", lithos meaning "rock", as many graptolite fossils resemble hieroglyphs written on the rock. Linnaeus regarded them as'pictures resembling fossils' rather than true fossils, though workers supposed them to be related to the hydrozoans; the name "graptolite" originates from the genus Graptolithus, used by Linnaeus in 1735 for inorganic mineralizations and incrustations which resembled actual fossils. In 1768, in the 12th volume of Systema Naturae, he included G. sagittarius and G. scalaris a possible plant fossil and a possible graptolite.
In his 1751 Skånska Resa, he included a figure of a "fossil or graptolite of a strange kind" thought to be a type of Climacograptus. The term Graptolithina was established by Bronn in 1849 and Graptolithus was abandoned in 1954 by the ICZN. Since the 1970s, as a result of advances in electron microscopy, graptolites have been thought to be most allied to the pterobranchs, a rare group of modern marine animals belonging to the phylum Hemichordata. Comparisons are drawn with the modern hemichordates Cephalodiscus and Rhabdopleura, according to recent phylogenetic studies, rhabdopleurids are placed within the Graptolithina, they are considered an incertae sedis family. On the other hand, Cephalodiscida is considered a sister subclass of Graptolithina; some of the main differences between these two groups are that Cephalodiscida is not a colonial organism so there is not a common canal connecting all zooids, which have several arms while Graptolithina zooids have a pair. Other differences include the type of early development, the gonads, the presence or absence of gill slits, the size of the zooids.
However, in the fossil record where tubes are preserved, it is complicated to make the distinction between groups. Graptolithina includes two main orders and Graptoloidea; the latter is the most diverse, including 5 suborders. This group includes Diplograptids and Neograptids, groups that had a great development during the Ordovician. Old taxonomic classifications consider the orders Dendroidea, Camaroidea, Stolonoidea and Dithecoidea but new classifications embedded them into Graptoloidea at different taxonomic levels. Graptolites have a worldwide distribution; the preservation and gradual change over a geologic time scale of graptolites allow the fossils to be used to date strata of rocks throughout the world. They are important index fossils for dating Palaeozoic rocks as they evolved with time and formed many different species. Geologists can divide the rocks of the Silurian periods into graptolite biozones. A worldwide ice age at the end of the Ordovician eliminated most graptolites except the neograptines.
Diversification from the neograptines that survived the Ordovician glaciation began around 2 million years later. Some of the greatest extinctions that affected the group were the Hirnantian in the Ordovician and the Lundgreni in the Silurian, where the graptolites populations were reduced. In the late Ordovician extinction, a recovery event known as the Great Ordovician Diversification Event or GOBE, influenced changes in the morphology of the colonies and thecae, giving rise to new groups like the planktic Graptoloidea; each graptolite colony originates from an initial individual, called the sicular zooid, from which the subsequent zooids will develop. These zooids are housed within an organic tubular structure called a theca, coenoecium or tubarium, secreted by the glands on the cephalic shield; the composition of the tubarium is not known but different authors suggest it is made out of collagen or chitin. The tubarium has a variable number of branches or stipes and different arrangements of the theca, these features are important in the identification of graptolite fossils.
In some colonies, there are two sizes of theca, the authoteca and the bitheca, it has been suggested that this difference is due to sexual dimorphism. A mature zooid has three important regions, the preoral disc or cephalic shield, the collar and the trunk. In the collar, the mouth and anus and arms are found; as a nervous system, graptolites have a simple layer of fibers between the epidermis and the basal lamina have a collar ganglion that gives rise to several nerve branches, similar to the neural tube of chordates. All this information was inferred by the extant Rhabdopleura, however, it is likely that fossil zooids had the same morphology. An important feature in the tubarium is the fusellum, which looks like lines of growth along the tube observed as semicircular rings in a zig-zag pattern. Most of the dendritic or bushy/fan-shaped o
