. Ocean wonders: a companion for the seaside. xible substance ?The answer reveals a wonderful contrivance which admirablymeets this difficulty. Over the shell we find a very delicatemembrane, vital, as its function proves ; this is insinuated be-tween the jointed plate-armorof the carapace, and steadilydeposits there a secretion ofcalcareous matter, so that eachseparate plate is simultaneous-ly increased in size ; and thusthe animal is enabled to ex-pand until the adult size isattained, when the secretionceases. As usually found, deadon the shore, the urchin is de-void of spines, and presentss
. Ocean wonders: a companion for the seaside. xible substance ?The answer reveals a wonderful contrivance which admirablymeets this difficulty. Over the shell we find a very delicatemembrane, vital, as its function proves ; this is insinuated be-tween the jointed plate-armorof the carapace, and steadilydeposits there a secretion ofcalcareous matter, so that eachseparate plate is simultaneous-ly increased in size ; and thusthe animal is enabled to ex-pand until the adult size isattained, when the secretionceases. As usually found, deadon the shore, the urchin is de-void of spines, and presentssomething the appearance ofa melon, the surface being marked with ten zones or divisions,five being larger than the alternating moiety. The urchins relationship to the star-fish may be illustratedby supposing that we bring all the five points of the star to-gether, filling up the interstices with a similar substance : wehave then a complete urchin, minus the spines. Or, take thepeel whole off of an orange, divide it into fifths, and bring the. Sea-Ukchin, ok Sea-Egg.—Top view,spines removed. ECHINOIDS AND SEA-CUCUMBER. 143 points up together, sticking needles in to simulate the spines,and we have an urchin, at least in shape. Like almost every known animal, this echinoid is muchhandsomer when alive and sailing about. The color is usuallyreddish brown or black. I have secured specimens of themin Bermuda with long, tapering spines a foot in length, andstanding boldly out like the quills upon a fretful porcu-pine ; the body or ball part not being larger than a hens-egg. Indeed, when these spines drop off and leave the shellycovering exposed, they very much resemble an egg, whichaccounts for their secondary name of sea-egg. When alive they are very shy, concealing themselves inholes and crevices of the rocks. They even go beyond this,and attempt complete seclusion from observation by coveringthemselves with bits of sea-weed, sand, or anything they canget hold of for the purpose, b
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Keywords: ., bookcentury1800, bookdecade1870, booksubjectmarineanimals, bookye
