Excerpt from The Palaeontographical Society, 1864, Vol. 16
The ambulacral areas are slightly sinuous, and furnished with four rows of small granules (fig. 2, e) closely set together, the marginal rows being the most uniform in their arrangement. The narrow poriferous zones lie in a deep groove formed by the prominence of the adjoining granules the pairs of small holes are obliquely inclined, with thickened septa, each having a small tubercle (fig. 2, 6) between them.
The inter-ambulacral areas have two rows of tubercles placed so near the poriferous zones that the inter-tubercular space in the middle of the area is about the same width as the ambulacra, whereby the ten rows of tubercles are situated nearly equidistant from each, thus imparting a regular appearance to this species (fig. 2, c, There are five tubercles in each row, which increase gradually in size from the peristome to the disc; the three basal tubercles are small and set closely together (fig. 2, whilst the two upper tubercles are large and wide apart (fig. 2, c); the mammillary eminence is depressed, the areolae are narrow (fig. 2, e), and their margin surrounded by a circle of well-defined granules (fig. 2, f). The tubercle is large and prominent, and the narrow boss on which it rests is destitute of crenulations (fig. 2, e, f) the summits of all the tubercles are perforated, those on the upper part of the test are, however, best preserved. A broad band of granula tions separates the two rows of tubercles; five or six rows of granules are closely placed together; and the granules in the band and those in the ambulacra are nearly of the same size.
About the Publisher
Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com
This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works.show more