. College collection of palaeontology. Siphonia (Hallirhoa) costata, Lamoureux. Polypothecia septemloba, Benett. The fossil Sponges belonging to this genus, have a comparatively symmetrical form. The body is bulbous and supported by a slender stem, which is composed of very fine parallel longitud- inal tubes, terminating on the surfaces of the central cavity. The base of the stem was fixed by root-like processes. Tlie genus does not occur above the Chalk. From the Upper Greensand, Westminster, England. No. 503. [1177, Cast]. Siphonia pyriformis, These pear-shaped Sponges are from the U
. College collection of palaeontology. Siphonia (Hallirhoa) costata, Lamoureux. Polypothecia septemloba, Benett. The fossil Sponges belonging to this genus, have a comparatively symmetrical form. The body is bulbous and supported by a slender stem, which is composed of very fine parallel longitud- inal tubes, terminating on the surfaces of the central cavity. The base of the stem was fixed by root-like processes. Tlie genus does not occur above the Chalk. From the Upper Greensand, Westminster, England. No. 503. [1177, Cast]. Siphonia pyriformis, These pear-shaped Sponges are from the Upper Greensand, Blackdown, England (a locality which has furnished many very interesting and peculiar forms of Sponges), and are now in the Ward Collec- tion of the University of Rochester. Stromatopora . This genus forms globular or hemispherical masses of large size. It con- sists of thin concentric laminae, penetrated by minute tubes. The genus ranges from the Lower Silurian to the Trias. This specimen is from the Hamilton Group, near Shueyville, Iowa. No. 505. [1185, Cast]. Ventriculites . The Ventriculites are the largest group of Cretaceous Sponges. They are shaped like a mushroom or funnel, tapering to a point l)elow, and attached by rootlets. The astonishing complication of their surface is shown by the fact, pointed out by Toulmin Smith, that in one specimen, only three inches high, nine millions of fibres were found! Like Siphonia, this genus is not found above the Cretaceous. From the Upper Chalk of Bridlington, England, and now in the Ward Collection of the University of Rochester. Size, 10 x 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 Ward's Natural Science Establishment, inc. Rochester
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