i!'- :: ! Dove-Miller: The Digestion of Wood by Teredo navalis 397 



members of the Advisory Committee appointed by the University of 

 California to cooperate with the San Francisco Bay Marine Piling 

 Committee. 



SUMMARY 



1. It has long- been a debatable question whether or not the boring 

 mollusks of the genus Teredo exercise any digestive action on the 

 wood particles which are swallowed during boring and retained for 

 a time in the caecum before being passed to the outside. The absence 

 of any conclusive evidence has suggested an experimental approach to 

 the problem. 



2. A chemical analysis has been made of three samples of wood 

 borings ejected by Teredo and of two samples of the original wood 

 from which the borings were derived. 



3. The results indicate that the wood loses about 80 per cent of its 

 cellulose and 15 to 56 per cent of its hemieellnloses during; its passage 

 through the digestive tract of Tere<li>. 



4. The carbohydrates which disappear are probably utilized as 

 food by Teredo. 



5. The woody portions of the ejected material have a uniform 

 composition of about 21 per cent cellulose and 55 per cent lignin. 

 Possibly this represents the ultimate residue which the animal is 

 unable to digest. 



6. The digestible carbohydrates in the wood may play an im- 

 portant rcle in the economy of Teredo in supplying energy for its 

 boring activities, supplementing the plankton diet upon which it 

 mainly depends for growth and repair. 



7. Digestion of wood constituents by Teredo produces optimum 

 conditions for the absorption of toxic substances contained in the 

 wood. 



8. Impregnation of wood is an efficient method of introducing 

 toxins into the borer's system, either for commercial preservation of 

 the wood or for testing experimentally the protective action of toxins, 

 because of the assured contact between toxin and digestive fluids. 



Transmitted November 22, 1922. 

 Laboratory or Plant Nutrition, 



Agricultural Experiment Station, 

 University of California, 

 and 

 Zoological Laboratory, 



University of California. 



