. Zoology : for students and general readers . Zoology. 106 ZOOLOGY. egg. When hatched, the larva is long, oval, and girded with four zones of cilia, with a tuft of cilia at the end, a mouth and anal-opening, and is about eight millimetres long. The body-cavity is formed by an inversion of the primitive layer which seems to correspond to the ectoderm. Within a few hours or sometimes days, there are indica- tions of the calcareous areolated plates forming the cup of the future crinoid. Soon others appear forming a sort of trellis-work of plates, and gradually build up the stalk, and lastly appe
. Zoology : for students and general readers . Zoology. 106 ZOOLOGY. egg. When hatched, the larva is long, oval, and girded with four zones of cilia, with a tuft of cilia at the end, a mouth and anal-opening, and is about eight millimetres long. The body-cavity is formed by an inversion of the primitive layer which seems to correspond to the ectoderm. Within a few hours or sometimes days, there are indica- tions of the calcareous areolated plates forming the cup of the future crinoid. Soon others appear forming a sort of trellis-work of plates, and gradually build up the stalk, and lastly appears the cribriform basal plate. Fig. 66, B, c, rep- resents the young crinoid in the middle of the larva, whose body is somewhat compressed under the 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 Packard, A. S. (Alpheus Spring), 1839-1905. New York : Henry Holt
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Keywords: ., bookcentury1800, bookdecade1870, booksubjectzoology, bookyear1879
