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ravings represent two species of the latter kind, which are, on account of the peculiar appearance of their skeleton, called glass sponges. Fig. 1 represents the "sprinkling pot sponge," _Eucleptella aspergillum_. It is generally found in very deep water throughout the Pacific. Specimens were found over fifty years ago, but, as they had to be brought up from depths between 500 and 800 fathoms, they remained very scarce and sold at fabulous prices. [Illustration: Fig. 1.--SPRINKLING POT SPONGE.--(_Eucleptella aspergillum_.)] The skeleton is formed by small crystals and long threads of vitreous silica, cemented together, during life, by protoplasm. They are arranged in longitudinal and annular bands so as to form a long curved cylinder, about nine to twelve inches long, the walls of which are about one inch in thickness. The threads and bands are interwoven with the greatest regularity, and when the skeleton is freed from the adhering organic matter, it looks extremely beautiful. The mode in which the intersecting bunches of crystals are connected is shown in Fig. 2. The upper end of the cylinder is closed by a perforated cover, which probably has given rise to the name of the sponge. The upper portion of the cylinder is surrounded by a few irregular, annular masses of organic tissue, which adheres loosely only to the skeleton. The lower end is formed by a bunch of long threads, rooting firmly in the ground. [Illustration: Fig. 2.--SPONGE CRYSTALS MAGNIFIED.] Up to about ten years ago the price of specimens of this sponge was very high. At that time, however, a colony of Eucleptellas was found near the cities of Cebu and Manila, in the East Indies, in a depth not exceeding 100 fathoms, and since they have appeared in larger quantities in the market. It is remarkable that, contrary to their habits, these organisms have immigrated into regions to which they were totally unaccustomed. Yet it must be regarded as a greater curiosity that they have been accompanied to their new abode by a few animals living in equally deep water and never met with before at depths less than three or four hundred fathoms. Among these animals is a _Phormosoma_ (water hedgehog), noted for its long spines. Glass sponges are not confined to tropical regions. They are met with in latitudes as high as the Faeroee Islands, where the beautiful _Holtenia Carpentaria_ abounds. It is represented in Fig. 3. Its cup-shaped skeleton is similar
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