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SPONGES,Various Forms,Multiple Antique Engravings ,Historical Print ,1894 Antique Wood Engraving SPONGES,Various Forms,Multiple Antique Engravings ,1894 Antique Wood Engraving Historical Collectible Spongology Art PrintThe sponges or poriferans (from the Greek poros "pore" and Latin ferre "to bear") are animals of the phylum Porifera. They are primitive, sessile, mostly marine, water dwelling filter feeders that pump water through their bodies to filter out particles of food matter. Sponges are among the simplest of animals. With no true tissues (parazoa), they lack muscles, nerves, and internal organs. Their similarity to colonial choanoflagellates shows the probable evolutionary jump from unicellular to multicellular organisms. There are over 5,000 modern species of sponges known, and they can be found attached to surfaces anywhere from the intertidal zone to as deep as 8,500 m (29,000 feet) or further. Though the fossil record of sponges dates back to the Precambrian era, new species are still commonly discovered. Sponges have several cell types:* Choanocytes (also known as "collar cells"), flagellated cells which function as the sponge's digestive system, are remarkably similar to the protistan choanoflagellates. The collars are composed of microvilli and are used to filter particles out of the water. The beating of the choanocytes flagella creates the sponge s water current.* Porocytes are tubular cells that make up the pores into the sponge body through the mesohyl.* Pinacocytes which form the pinacoderm, the outer epidermal layer of cells. This is the closest approach to true tissue in sponges.* Myocytes are modified pinacocytes which control the size of the osculum and pore openings and thus the water flow.* Archaeocytes (or amoebocytes) have many functions; they are totipotent cells which can transform into sclerocytes, spongocytes, or collencytes. They also have a role in nutrient transport and sexual reproduction.* Sclerocytes secrete calcareous or siliceous spicules which reside in the mesohyl.* Spongocytes secrete spongin, collagen-like fibers which make up the mesohyl.* Collencytes secrete collagen.* Spicules are stiffened rods or spikes made of calcium carbonate or silica which are used for structure and defense.* Cells are arranged in a gelatinous non-cellular matrix called mesohyl.Sponges have three body types: asconoid, syconoid, and leuconoid. Asconoid sponges are tubular with a central shaft called the spongocoel. The beating of choanocyte flagella force water into the spongocoel through pores in the body wall. Choanocytes line the spongocoel and filter nutrients out of the water. Syconoid sponges are similar to asconoids. They have a tubular body with a single osculum, but the body wall is thicker and more complex than that of asconoids and contains choanocyte-lined radial canals that empty into the spongocoel. Water enters through a large number of dermal ostia into incurrent canals and then filters through tiny openings called prosopyles into the radial canals. There food is ingested by the choanocytes. Syconoids do not usually form highly branched colonies as asconoids do. During their development, syconoid sponges pass through an asconoid stage. Approximate Overall Size: 6 X 9 1/2 inches CONDITION: Book Plate - Excellent Condition. As Scanned. German Text. Beautiful with excellent detail. SINGLE PAGE BLANK ON THE BACK Single Page Print. Blank on the back - TEXT IN GERMAN. Approx Image Sizes : 8 x 5 ins - Approx Overall Size with Margins: 6 x 9 1/2 inches. Excellent Condition. Image is clean, clear, sharp with beautiful detail. As scanned. Printed on cream color coated paper. This beautiful print would look great matted and framed. Or an art supply store can provide you with a selection of frames for old art treasures.
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