Figure No. TITLE Page 



97. Graph representing activity of Teredo navalis in water of various salinities 255 



98. Graph representing length to which siphons of Teredo navalis are extended in water of various 



salinities 256 



99. Graph of the salinity of water at Crockett during the season of 1921-22 262 



100. Graph of salinity of bay water, Martinez wharf 264 



101. Graphs of physical and chemical conditions in Carquinez Strait at Crockett after 266 



102. Graphs of physical and chemical conditions in San Francisco Bay at Dumbarton 266 



103. Graphs of physical and chemical conditions in San Francisco Bay at Oakland Mole 266 



104. Graphs of physical and chemical conditions in San Francisco Bay at the Ferry Building. . . 266 



105. Graphs of physical and chemical conditions in the Golden Gate at Fort Scott 266 



106. Curves showing number of ridges per nun. on shell of Teredo from three stations 270 



107. Series of shells of Teredo navalis from Crockett, showing effect of environment on develop- 



ment of ridges 271 



108. Shells from top and bottom at Crockett 273 



109. Comparison of shells from Goat Island, Dumbarton and Crockett 274 



110. Diagram of Teredo shell, showing method of obtaining index of auricle 275 



HI. Graph representing index of auricle of shell of Teredo at three different stations 276 



112. Variations in denticulation and color of shells of Teredo 277 



113. Variations in pallets of Teredo navalis from Goat Island and Oakland Harbor 279 



114. Variations in pallets of Teredo navalis from Crockett, Dumbarton and Goat Island 280 



115. Photomicrograph of cross section of gravid female Teredo navalis 285 



116. Pile from Seattle, entirely destroyed at mud line by Bankia selacea 293 



117. Martesia striata from Pearl Harbor and Cavite 296 



118. Attack of Martesia striata at Pearl Harbor 297 



119. Test piece attacked by Martesia striata and Teredo parksi at Pearl Harbor 299 



120. Views of Pholadidea, Platyodon, and Petricola 302 



121. Pholadidea penita in concrete pile-jackets 303 



122. Pholadidea gabhi in a loose block of sandstone from F'ort Mason 305 



123. Limnoria in place attacking wood 307 



124. Limnoria lignorum, Rathke 308 



125. Limnoria lignorum, after Hoek (1893) 310 



126. Ventral view of head of male Limnoria (after Hoek) 311 



127. Mandibles of Limnoria (after Hoek) 312 



128. Mouthparts of Limnoria (after Hoek) 313 



129. Internal anatomy of Limnoria lignorum, reconstructed from sections 315 



130. Cross sections of Limnoria lignorum 317 



131. Limnoria lignoium, photographed alive in burrows 318 



132. Limnoria lignorum at work on the surface of wood 319 



133. Illustrations of dififerent degrees of Limnoria attack 322 



134. Activity of Limnoria lignorum in water of various salinities 328 



135. Limnoria andrewsi from Tutuila 331 



136. Test blocks from Tutuila and Honolulu, showing attack by Limnoria andrewsi and 



Cbetura insulae 332 



137. Sphaeroma pentadon ^^^ 



138. Attack by Sphaeroma pentadon on test block in Petaluma Creek 334 



139. Pile attacked by Sphaeroma between tide levels 335 



140. Chelura terebrans 336 



141. Chelura insulae from Tutuila 337 



142. Shipping box for water samples, San Francisco Bay salinity investigation 346 



143. Sketch of untreated test piece to be planted for seasonal records of activity of marine borers. . 349 



