Elementary zoology (1902) Elementary zoology elementaryzoolog00kell Year: 1902 BRANCH PORIFERA: THE SPONGES others in deeper water, even to the deepest depths yet explored. They are found in all seas, though especially abundantly in the Atlantic Ocean and Mediterranean Sea. Form and size.—The shape of the simplest sponges is that of a tiny vase or nearly cylindrical cup, hollow and attached at its base. At the free end there is a large opening. But there is a great deal of variety in the form and size of different sponges. There is, indeed, much varia- tion in the shape and general character
Elementary zoology (1902) Elementary zoology elementaryzoolog00kell Year: 1902 BRANCH PORIFERA: THE SPONGES others in deeper water, even to the deepest depths yet explored. They are found in all seas, though especially abundantly in the Atlantic Ocean and Mediterranean Sea. Form and size.—The shape of the simplest sponges is that of a tiny vase or nearly cylindrical cup, hollow and attached at its base. At the free end there is a large opening. But there is a great deal of variety in the form and size of different sponges. There is, indeed, much varia- tion in the shape and general character of different individuals of the same species. Unlike most other animals, sponges are fixed, and the character of the surface to which a sponge is attached has much influence upon its shape. If this surface is rough and uneven the sponge may follow in its growth the sinuosities of the surface and so become uneven and distorted in shape. At best, only a few kinds of sponges have any very even and symmetrical shape. Most of them are very unsym- metrical and grow more like a low compact bushy plant than like the animals we are familiar with. The smallest sponges are only I mm. (^ in.) high, while the largest may be overFlG- 12. — The skeleton of a . '-glass' sponge (skeleton com- a meter (39 in.) in height. In poSed of siliceous spicules) from color living sponges may be JaP:m- (From specimen.) red, purple, orange, gray, and sometimes blue. Most sponges have the whole body of one color.
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