. Cassell's natural history. Animals; Animal behavior. NATVEAL HISTORY. soft tissue in bands. The lower part of the axis is not covered with zooids, and the upper part may have its surface with zooids on one or both sides in simple series, in-spiral series, or in groups on one or both sides. When the upper part of the axis is branched, the pen-shape may be single or double, and crowds of zooids with spinules are arranged on one edge. The ectoderm usually contains cal- careous spiculse. The Sea-pens live in shallow water, and also at great depths, and their distribution in the ocean is very wid
. Cassell's natural history. Animals; Animal behavior. NATVEAL HISTORY. soft tissue in bands. The lower part of the axis is not covered with zooids, and the upper part may have its surface with zooids on one or both sides in simple series, in-spiral series, or in groups on one or both sides. When the upper part of the axis is branched, the pen-shape may be single or double, and crowds of zooids with spinules are arranged on one edge. The ectoderm usually contains cal- careous spiculse. The Sea-pens live in shallow water, and also at great depths, and their distribution in the ocean is very wide. The sub-family Pennatulse contains the genus Pennatula, in which the zooids are on the ventral and lateral sides of the stem, there being always a bilateral arrangement of them on the long cylindrical pinnate stem also. Many are very phosphorescent, and most live in shallow water, some going down to three hundred fathoms. Their colours are often brilliant red, and the specimens may be a foot in length. The stalk, or lower part of the axis, swells ovit, and then terminates in a slender end, or it may be short and cylindrical. The spicules have the tint of the whole. The zooids are on the tufts, and not on the stem, in the genus Pteroeides. In the genus Virgularia the root is stout and bent, the axis very long and often curved, and the zooids are on either side, on the shoi-t pinnules. Calcareous needles aie scanty in the stalk and tentacles. In the genus Scytalium, the zooids, placed side by side, resemble the half of a young leaf, and the pinnae are thick, whilst in Pavonaria, the zooids are on the thick edge of the four-sided stem. A magnificent form, called Anthoptilum thomsoni, after the late diiector of the Challenger Expedition, has a round and long axis, and the zooids are in many short rows on' it. It was found at six hundred fathoms' depth, south of Buenos Ayres, and another species at a depth of 1,200 fathoms. The family Umbellulidfe have a long sterile axis, and fr
Size: 1118px × 2236px
Photo credit: © Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade1890, booksubjecta, booksubjectanimals
