. The Cambridge natural history. Zoology. 7 .. V . C, ⢠â ⢠A W^^^iJ'M^^ ^S ^S ^^^^^ ^^Mf^M^^^akk. Fig. 194.âViews of portions of the aboral surface of different genera of Asteroidea in order to show the main varieties of skeleton. A, Solasler, showing spines arranged in sheaves ; B, Pteraster, showing wehs forming supra-dorsal membrane supported by diverging spines ; C, Astropecten, showing paxillae ; D, Nardoa, showing uniform plating of granules. x 8. (After Sladen.) dorsal tent is formed (a structure characteristic of the Pter- asteridae), or (2) the members of a sheaf may become arrange
. The Cambridge natural history. Zoology. 7 .. V . C, ⢠â ⢠A W^^^iJ'M^^ ^S ^S ^^^^^ ^^Mf^M^^^akk. Fig. 194.âViews of portions of the aboral surface of different genera of Asteroidea in order to show the main varieties of skeleton. A, Solasler, showing spines arranged in sheaves ; B, Pteraster, showing wehs forming supra-dorsal membrane supported by diverging spines ; C, Astropecten, showing paxillae ; D, Nardoa, showing uniform plating of granules. x 8. (After Sladen.) dorsal tent is formed (a structure characteristic of the Pter- asteridae), or (2) the members of a sheaf may become arranged in a circle round a central vertical axis so that a structure like a capstan is produced, which is called a " paxilla " (characteristic of Astropectinidae, Porcellanasteridae, and Archasteridae). The axis,-^ as shown by its development, represents the plate which bore the bundle of spines. Again, the skeleton may consist of plates with a close covering of granules (Pentagonasteridae, etc.). Lastly, in Porania spines are absent, the plates being deeply embedded in a thick leathery skin. ' Ludwig, "Die Echinodermen des Golfes von Neapel," pp. 68, 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 Harmer, S. F. (Sidney Frederic), Sir, 1862- ed; Shipley, A. E. (Arthur Everett), Sir, 1861-1927. ed. [London, Macmillan and Co. , Limited; New York, The Macmillan Company
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectzoology, bookyear1895
