336 



bridge of the Northwestern Pacific Railroad. The slight attack by Sphaeroma during 

 this period is practically all limited to the region of saw-cuts made in the board to 

 facilitate the removal of sample blocks. In these crevices the borers found lodgement 

 and worked a short distance in each direction. It is interesting to note that the red- 

 wood strip was attacked in preference to the Douglas fir board. Teredo and Bankia 

 iisualh' show a greater or less aversion to redwood. In this case, at least, Sphaeroma 

 has not attacked the fir board at all, except to scrape a few depressions in its surface 

 in the crevice between it and the redwood strip. The redwood seemed to be somewhat 

 softer than the fir, which may explain the preferential attack. 



The presence of a few barnacles indicates that the water at this locality is brackish. 





Fig. 1-40. (1) Chelura terebrans, male, from Charleston, S. C. Dorsal view. X 11. 

 (2) Same, lateral view. X 11. 

 (3 and 4) Dorsal and ventral views of female Chelura. X 5. 



The excavations made by Sphaeroma in piling are \er\ characteristic in appear- 

 ance. They have large openings, up to nearly one-half inch in diameter, and often 

 considerably longer than wide. They follow the grain of the wood, and do not exhibit 

 the expansion inward characteristic of the burrows of moUuscan borers. They are 

 usually shallow, but some ha\e been found three or four inches in depth. 



Sphaeroma works mainly between high and low tides, although found at all levels 

 on piling. Between tide levels it gives the piling a pitted appearance with its large, 

 open, dark-colored burrows. 



Nothing is known of the development or breeding habits of this species beyond 

 the fact that the eggs are carried on the abdomen of the mother for a time, and that 

 immature specimens are found in the spring, summer and fall in the burrows with the 

 adults. It is not improbable that it breeds throughout the year as does Limnoria 

 in San Francisco Ba\'. 



