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This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1921 Excerpt:...openings up to nearly one-half inch in diameter, enter the wood horizontally or turn more or less abruptly and run with the grain in the softer layers of the wood. They do not exhibit the expansion characteristic of the molluscan burrows. Sphaeroma works mainly between high and low tide, though found at all levels on piling. Its workings are obscured (pl. 11, fig. 2) in deeper water by the more intense activities of Limnoria and the growth of other marine organisms. Between tide levels it gives to the piling a pitted appearance with its large, open, dark-colored burrows. Its work is erratic in that often only certain piles are subject to its attacks while neighboring ones may be untouched. It sometimes runs channels on the surface of wood, especially in the more deeply submerged piling. Barrows (1919) has found this species burrowing into tuff and friable sandstone at Rodeo on San Pablo Bay, where they excavate burrows ranging from 2 millimeters long and 6 millimeters deep occupied by young individuals, up to burrows 9 millimeters in diameter and 35 millimeters deep. They also excavate holes with great enterprise in chalk when placed in aquaria under observation. They are hardy ubiquitous creatures finding a home and ' digging in' into a great variety of substrates, such as soft mud, wood, or even rock itself. They dig for shelter rather than food and except in a few restricted localities are industrially of less consequence than any of the other borers we have discussed. Distribution Sphaeroma pentodon has a wide range of distribution in our locality. It has been found at Sausalito, Tiburon, Black Point, the Mare Island dikes, in Napa Creek, along Carquinez Strait and upstream to Antioch in water of low salinity. It also occurs along the western water fron...