. Elementary text-book of zoology. SYCANDRA. 103 CHAPTER XII. TYPE OF PORIFERA. SYCANDRA. Phylum Porifera. Class Calcarea. Sycandra compressa is a small marine i7- â o f J 11 11 ..⢠^ r J £ J I^ig- 37.âSycandra sponge of a dull yellow tmt, found fixed ^ compressa to rocks or weeds between tide marks. Oscuium Form and ^^ ^^'" ^'^^P^ ^'l^^ ^ ^^t- length up to i^ men. It / ('^"''⢠is like all sponges axially symmetrical (though the symmetryis often obscured), hence we can distinguish merely a main axis, a base, and an apex. The base is fixed to a foreign body and the apex has a large
. Elementary text-book of zoology. SYCANDRA. 103 CHAPTER XII. TYPE OF PORIFERA. SYCANDRA. Phylum Porifera. Class Calcarea. Sycandra compressa is a small marine i7- â o f J 11 11 ..⢠^ r J £ J I^ig- 37.âSycandra sponge of a dull yellow tmt, found fixed ^ compressa to rocks or weeds between tide marks. Oscuium Form and ^^ ^^'" ^'^^P^ ^'l^^ ^ ^^t- length up to i^ men. It / ('^"''⢠is like all sponges axially symmetrical (though the symmetryis often obscured), hence we can distinguish merely a main axis, a base, and an apex. The base is fixed to a foreign body and the apex has a large opening, the oscuium, which *''="='!'os=a-'"'='^4''*''"*''"''â leads into the interior of the sponge. natura size. If the living Sycandra be watched carefully in a vessel of water, it will easily be seen that currents of water are, with- out interniission, pouring out of the oscuium. Further examination of the surface of the sponge would reveal an immense number of extremely minute openings all over the surface, into which the water perpetually flows. These are termed the pores. If a hand-section of the sponge be made it is seen to be hollow, and the wall appears of even thickness all round the central cavity. This cavity is called the para- gastric cavity, opening through the oscuium to the exterior. The walls of the sponge are of a somewhat firm leathery int ai consistency and when boiled in potash the animal matter is destroyed, leaving a residue of numerous small spicules, transparent and tri-radiate in shape. These hard spicules dissolve immedi- ately, with effervescence, on the. application of any dilute. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Masterman, Arthur Thomas. Edinburgh, E. & S. Livingstone
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Keywords: ., bookcentury1900, bookcollectionbiod, bookdecade1900, bookyear1902
