. A manual of zoology. Zoology. Fie. ,;oj. l''ic. 303. Fie,. ;o;.—i'lvfJiMstcr suh,!i-i'yi-ss-i(S (after .\,uas?i.:V .\lioral view, sIiowIhl; the [ict,iloiil en Is of llio ainliul;UT,il areas. Fig. ^o^—Dia^rammalie loiiL;Uiulinal section through a sea urchin. Tn the arrangement of llie ambulacra two niodihe itions, the band form and the petaloid, occur. In the first (Regularia) the ambulacra are eqiially de\"eloped from peristome to ])eriproel i^lii;. 301). In the second oral ,ind aboral regions may be distinguished (fiL;, 30::). In the oral region alone ai'c loeo- motor feet always prese
. A manual of zoology. Zoology. Fie. ,;oj. l''ic. 303. Fie,. ;o;.—i'lvfJiMstcr suh,!i-i'yi-ss-i(S (after .\,uas?i.:V .\lioral view, sIiowIhl; the [ict,iloiil en Is of llio ainliul;UT,il areas. Fig. ^o^—Dia^rammalie loiiL;Uiulinal section through a sea urchin. Tn the arrangement of llie ambulacra two niodihe itions, the band form and the petaloid, occur. In the first (Regularia) the ambulacra are eqiially de\"eloped from peristome to ])eriproel i^lii;. 301). In the second oral ,ind aboral regions may be distinguished (fiL;, 30::). In the oral region alone ai'c loeo- motor feet always present, but these are irregularly arranged. In die aboral area the ambulacra are branchial or tenlaeular and are regularly aiTanged, their pores bounding li\e petal-like hgures arouiul the periproei, \erv dislinci aller renioxal of the spines (fii;. ^oob In the Regularia, the tddarida- excepted, the interambulacral plates around the peristome show Twe pairs of notches for the gills, live pairs of thin-walled branching extensions of the body ca\ity. Ambulacral and interambulacral fields both end at the periproct with an unpairetl plate, the live ambulacral plates (U-niiiiuilid of morphology) being called oailar plalcs, since they often hear pigment spots formerly regarded as eyes. Ivich is jierforaled by the end of the radial canal and nerve. The live interarnhulacral plates (Ihisiilia) are called i^fiiilal philes, since they usually conlaiir the openings of the genital duels. One is often nradreporite as well. Inside of Ihe body is a spacious cadom, to the\yalls of which the thin- ^vaIled alimentary tract is fastened by a mesentery. In the (dypeastroids this tract forms a simple siiiral, but elsewhere it asceiuls from the motilli, turning once, and then, lieiuling on itself, coils in the reverse direction to. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustratio
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectzoology, bookyear1912
