Glaucus or The wonders of the shore Author:Charles Kingsley Purchase of this book includes free trial access to www.million-books.com where you can read more than a million books for free. This is an OCR edition with typos. Excerpt from book: APPENDIX. PLATE I. ZOOPHYTA. POLYZOA. The forms of animal life which are now united in an independent class, under the name Polyzoa, so nearly resemble ... more »the Hydroid Zoophytes in general form and appearance that a casual observer may suppose them to be nearly identical. In all but the more recent works, they are treated as distinct indeed, but still included under the general term " Zoophytes." The animals of both groups are minute, polypiform creatures, mostly living in transparent cells, springing from the sides of a stem which unites a number ofindividuals in one common life, and grows in a snruL- like form upon any submarine body, such as a shell, a rock, a weed, or even another polypidom to which it is parasitically attached. Each polype, in both classes, protrudes from and retreats within its cell by an independent action, and when protruded puts forth a circle of tentacles whose motion round the mouth is the means of securing nourishment. There are, however, peculiarities in the structure of the Poly- zoa which seem to remove them from Zoophytology to a place in the system of nature more nearly connected with Molluscan types. Some of them come so near to the compound ascidians that they have been termed, as an order, " Zoophyta ascidioida." The simplest form of polype is that of a fleshy bag open at one end, surmounted by a circle of con tractile threads or fingers called tentacles. The plate shows, on a very minute scale, at figs. 1, 3, and 6, several of these little polypiform bodies protruding from their cells. But the Hydra or Fresh-water Polype has no cell, and is quite unconnected witli any root thread, or with other individuals of thesame species. It is perfectly free, and so simple in its structure, that when the sac which forms its body is turned inside o...« less