. The Cambridge natural history. Zoology. ECHINUS—CORONA 511 The number and variety of the pedicellariae, then, is an eloquent testimony to the dangers to which the soft sensitive skins of the Sea-urchin and other Echinodermata are exposed,, and afford confirmatory evidence in support of the view ex- pressed above, that the method adopted to defend the skin was one of the great determining features which led to the division of the Asteroidea into different races. The corona consists of five radial or " ambulacral" bands of plates and five interradial, or as they are usually termed, &
. The Cambridge natural history. Zoology. ECHINUS—CORONA 511 The number and variety of the pedicellariae, then, is an eloquent testimony to the dangers to which the soft sensitive skins of the Sea-urchin and other Echinodermata are exposed,, and afford confirmatory evidence in support of the view ex- pressed above, that the method adopted to defend the skin was one of the great determining features which led to the division of the Asteroidea into different races. The corona consists of five radial or " ambulacral" bands of plates and five interradial, or as they are usually termed, " inter-. FlG 227.—Dried shell oi Hchinus esculentus, showing the arrangement of the plates of the corona, x 1. 1, The anus ; 2, periproct, with irregular plates; 3, the madreporite ; 4, one of the other genital plates ; 5, an ocular plate ; 6, an mter- ambulacral plate ; 7, an ambulacral plate ; 8, pores for protrusion of the tube-Jeet; 9, tubercles of the primary spines, primary tubercles. ambulacral" bands of plates—ten in all. Each of the ten consists of two vertical rows of plates throughout most of its extent, and each plate is studded with large bosses, or "primary tubercles " for the primary spines, smaller bosses called " second- ary tubercles" for the secondary spines, and finally, minute elevations called " miliary tubercles " for the pedicellariae. Even in the dried skeleton, however, the ambulacral plates can be. 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
